Having that reaction to declines really isnt normal IMO, and I would be concerned. Maybe you arent breathing right when you do the lift? Concentrate on doing the correct breathing pattern and not holding your breathe. It sounds like your BP is only too high while you are lifting. Being on a decline never did anything of that sort to me. I did used to have a bleeding head after doing squats though! My scalp would be pouring out trickles of blood and I didnt even know it. I only learned after people told me. After inscpecting my scalp I could see that tiny little pimples had popped and were bleeding all over! Sure my BP was too high during the lift. The kind of gear you may be on could affect this too I believe.