I always felt great after a night of smoking heroin, until I was addicted. I don't remember ever having a "hangover," just withdrawals. Maybe that's what you're experiencing? Think about that and be honest with yourself. If it's withdrawals, you have two choices. Try to manage the addiction (which for me failed epically), or face the music and fight through the withdrawals and say goodbye to heroin.
I definitely don't want to preach. I loved heroin for a long time, and I don't judge anyone who loves it now. But it turned on me, and while I've been clean now for almost six months, the ramifications on my mind and nervous system are ongoing.
Maybe I'm the only one who never had a hangover, or maybe I eased my way into addiction and never used much more than my tolerance could cope with, but that's my two cents. And even if you are addicted, maybe you'll be able to actually manage it. But I couldn't, and my story is the only one I can tell.
Good luck out there.