Beside the obvious (and often very revealing) infrared from increased body temperature, there are electromagnetic emissions from muscles and the brain.
Muscle potentials (measured with electromyography, EMG) are on the scale of millivolts when measured on the skin. Brain activity (measured with electroencephalography, EEG) produce microvolt potentials. A tense person will have a high muscle tonus and hence produce muscle potentials. Different brain states have characteristic EEG patterns, but they have typically less to do with what feeling the brain experiences and more with the general level of arousal and attention.
Both EMG and EEG are oscillating electrical potential (in the <100 Hz range) so they radiate a bit. However, they are multipoles and hence decay faster than dipole radiation - I would be surprised if they could be detected above the normal electrical noise level from more than a few centimeters away.
Negative emotions do have bad effects on the body, but these are mediated through stress hormones (glucocorticoids) that decrease immune function, memory and other things. The electromagnetic fields have nothing to do with it.