What does it mean to be/have a negative charge? what does it mean to be negatively charged. I can't find anything on it and i would love to be able to finally understand what it means to be negatively charged.
 A: The decision to call one kind of charge positive and one kind of charge negative is entirely arbitrary. 
All electric charges are either positive or negative. 
It is convenient to express charge in terms of rational numbers (the smallest theoretically possible charge in the Standard Model is +1/3 or -1/3 in electron charge units), but there isn't a fundamental reason that we have to use that terminology. We could call charges like those in the proton "West charges" and charges like those in the electron "East charges", for example, without any change in meaning.
In other words, in the context of electrical charges, positive and negative are "directions" in charge space. Negative charges are the inverse of positive charges but they are not "less than" positive charges. An electrical charge of zero just means that something is electromagnetically "neutral", i.e. equidistant between positive and negative.
But electric charge is not like, for example, mass, for which a negative mass is a non-physical. To the best of our knowledge there is no such thing as negative mass, which is something that we have never observed which is only defined mathematically. But, the real physical universe is full of positive and negatively charged particles, in almost precisely the same amounts.
One hundred and eighty years ago, when electromagnetism was just becoming a science, somebody simply adopted a sign convention which implies that the charge of an electron is -1 in electron charge units, and the charge of a proton is +1 in electron charge units. If physicists in the Amazon jungle had developed electromagnetism independently of physicists in Europe, and the Amazonian physicists decided that the charge an an electron would be +1 and the charge of a proton would be -1, their calculations would produce precisely the same predictions about the electromagnetic forces between objects as the European physicists would. The direction of the sign is an entirely arbitrary rule of the road.
Specifically:

In 1839, Michael Faraday showed that the apparent division between
  static electricity, current electricity, and bioelectricity was
  incorrect, and all were a consequence of the behavior of a single kind
  of electricity appearing in opposite polarities. It is arbitrary which
  polarity is called positive and which is called negative. Positive
  charge can be defined as [and was originally defined as] the charge
  left on a glass rod after being rubbed with silk.

We didn't know why positive charged things had positive charges and negatively charged things had negative charges until much later. The electron was discovered in 1874 by George Johnstone Stoney, and the electron-proton model of the atom was proposed in 1911 by Antonius van den Broek and proven experimentally in 1913 by Henry Moseley. But, by 1913, the electric charge sign convention was already 74 years old.
Pursuant to Coulomb's Law, a positive charge and a positive charge repel each other, a negative charge and a negative charge repel each other, and a positive charge and a negative charge attract each other.
(The strength of that attraction or repulsion is inversely proportionate to the square of the distance between them. So, if the strength of the electromagnetic force between two identical charges at a distance of 1 units is 16, the strength of the electromagnetic force between them at a distance of 2 units is 4, and the strength of the electromagnetic force between them at a distance of 3 units is 16/9th (i.e. about 1.78), for any units you choose.)
When we say that something has a positive electrical charge, we simply mean that it has the same kind of charge as a proton. And, when we say that something has a negative electrical charge, we simply mean that it has the same kind of charge as an electron.
A: When a particle has a negative charge, it means it attracts, rather than repels, a positive charge. If you prefer to think in terms of fields, it means that the field points radially inward toward the particle rather than radially outward away from it.
A: Everything in the universe is made of atoms. Atoms are made up of protons, neutrons and electrons. Neutrons have a net charge of 0, while protons have a +1 relative charge and electrons a -1 charge. Atoms always have an equal number of protons and electrons, so they have no resultant charge. But, they can be ionised which means they either gain or lose electrons due to chemical reactions, forces, voltage etc.
Ions that gain electrons, therefore have a negative resultant charge, while ions that lose electrons have a positive resultant charge. This effect of “resultant charge” can also be seen on a more macro scale.
Take an acetate rod and a cloth/duster. If you use friction between the cloth and rod, you can cause electrons from the rod to move to the cloth. This is because the acetate rod’s atoms have weak electrostatic attractions to their valence electron, because the electron that can be moved due to friction is lots of orbital shells away from the atomic (positive) nucleus, so their attraction is weak. 
Back to the duster and cloth scenario: so when the electron from the rod is moved to the duster via friction, it now means there is an extra negative charge on the duster and one less negative charge on the acetate rod. 
So now the rod is positively charged, due to losing an electron, and the cloth is negatively charged due to gaining an electron. And just like how the positive nucleus attracted its valence electron, the duster and rod now attract to each other due to opposite charges.  This phenomenon is best described electric fields by the way, so if you want to continue learning about charges that’s a good place to start.
