Brownie made me nauseous

I'm gonna start off by saying that I've never used marijuana before until last spring break, so I had no idea what to expect. All my friends are stoners and always asked me if I wanted to try smoking or edibles (I don't want to try smoking because I don't want to inhale any smoke), so I finally decided to try a brownie over spring break and chill with them all weekend. I did research, so I knew it would take a while to kick in, and that the high would last longer than if I were to smoke, and I also read a few things saying that you get a calmer high from edibles, so I was feeling pretty good. My friend said the brownie had around 15 mg of THC in it, so looking back on it i probably should have only eaten half the brownie to start, but I thought that it wasn't too much at the time. I had a very large meal before I consumed the brownie, so it took around 3 hours to start kicking in, and by that time I had passed out. I only really felt the effects when I woke up in the middle of the night. My body felt extremely slow, like it was taking 3 seconds longer than my brain was, my thoughts were all discombobulated, I was extremely dizzy, and not in a pleasant way, and I was also very nauseous. I slept through most of the high and didn't have any dreams, but when I woke up I still felt the dizziness and nausea the rest of the day, and I had a lingering groggy feeling the following couple of days. I'm assuming my bad experience was probably because of too much THC for my first time using, but I'm extremely uneducated when it comes to edibles so I was wondering if that nauseous feeling was from too much weed, the wrong kind of weed, my body's chemistry, or something else. Any help is appreciated! (sorry if this is posted to the wrong category)