I have been tired from test injections. Also, it may be nerves. It is not natural to inject yourself so your body will adrenalize prior to injections and then assuming you do not fuck up, will let down as it was no big deal afterward.
It may just be nerves and you get a little light headed and feel tired. give it some time and see if it passes. My friend used to feel faint after injecting I never have and I think he did because of nerves
frequent injections will definetelly affect your nervous system...the impact is is for this reason that after an injection your injection feels like post training soreness...well not w/ compounds such as EQ,deca,but frequent prop,suspension,sust injections all feel that sure to verify your CK levels as well on your next blood test,seeing as how frequent injections affect these levels in a negative your body just needs recup from frequent injections...