Pills and weed will make your heart race. I guess coming down from the pills and weed, you'll feel an exaggerated 'low'.

I was taking two drugs because the doctors couldn't figure out where the pain in my foot was coming from, after my 30th car accident. The 'brain-candy' was Topamex and the other was a muscle relaxer (Baclophyn). I took those, in combination, for half-a-year, and, everyday, I smoked herb. It freaked me out, everyday, and I loved it. But, I don't suggest it. It got me into some strange situations.