I'm not caster heavy, so the one heal spell i have is pretty worthless, and usually stores have only 2 or 3 health potions to buy at a time. Does anyone know where i can get a good amount of them?

I recommend dungeon diving. I've been finding a ton lying around, though my recent encounters with mammoths and the first dragon depleted my supplies significantly >:

Yeah I've noticed the alchemist lady in Whiterun doesn't have very many. I've run into a few encounters where I could have used a lot more than I had, hehe.

Dungeon diving worked well until about level 15 then i started finding almost no potions

You can brew a health potion from blisterwort and wheat, so if you happen to come across any of that I would pick it up.

You really need to brew your own. But I haven't been to Solitude yet, maybe there's somebody there...