[driftdiver]

Benadryl works well for allergic reactions. Not as powerful or quick as an epi-pen but at least you can by it over the counter.

[Sarajevo]

Benedryl is the counter for allergic reactions since it is an aghonist-antagonist. It actually removes the histamine from the receptor site and replaces it.
Epinephrine, OTOH, is used as a bronchodilator since many allergic reactions are powerful enough to constrict the airway. Epinephrine (aka adrenaline)is produced naturally by the adrenal cortex on the kidneys.

bgill - Are you sure that you are having a reaction to the epi, or another component of the injection? The dilation effect on smooth muscle could also cause your BP to drop at a high rate causing a transitory syncope effect.