I always got sleepy after a shot. Even smoking I could fall asleep holding the bowl .. crazy I never knew why
You are probably taking a cathinone which is meant to mimic a similar effect.
It could be one of the following below:
Mephedrone: Short-acting, moderate stimulation and extremely addictive. (More so than meth for me. Most addictive drug I've tried). Not intensely euphoric, but enough to keep you dosing until you have picked every white crumb that looks like meph out of the carpet. HORRIBLE comedown. 70% cocaine-like; 30% MDMA-like.
Methylone: Short-acting, stimulating and extremely euphoric. More like what I imagined "ecstasy" to be than MDMA was. Could re-dose for days and still get high. Little-to-no comedown. Like a shorter acting, less toxic feeling MDMA. Very high therapeutic value IMO.
4-EMC: The most similar thing to mephedrone I've found, but far less fiendish and not as stimulating. Moderately euphoric and mixes well with "straight" stimulants like 2-FA (in low doses of course).
4-MEC: Nothing like 4-MMC or 4-EMC. Moderately sedating and stoning, but without any real euphoria. Also combines well with other stimulants. Heart palpitations were mild but noticeable, especially on the comedown.
3-FMC: Mild, stimulating caffeine-like compound. No empathogenic effects or euphoria, but a decent functional stim.
Ethylone: Smells/tastes identical to methylone but lacks the "magic". Not stimulating enough for my taste and slightly dysphoric. Not bad when taken with another stim like 2-FMA.
5ME: EXTREMELY sedating and drowsy. Zero euphoria until the comedown when I got my energy and brain function back. Eyes rolling back in the head, but not in a pleasant way. Far too heavy for my taste.
Benzedrone (4-MBC): No noticeable psychoactive effect whatsoever.