So this is going to sound strange, but I was wondering if anyone knows if wearing a sweatsuit while exercising will actually burn more calories and help with weightloss or if you just get dehydrated?

I would recommend avoiding it. You can become overheated and possibly harm yourself. I'm assuming you are referring to a fleecy knit type sweat suit, right? Or do you mean the plastic (sometimes silver) sauna suits? Those can actually be deadly. This post has more info on that.

Your best bet is probably to wear comfortable clothing so your body can breathe and perspire properly. You'll probably be able to exercise longer, too.