Pregnancy

So I've recently had unprotected sex multiple times and a while after have started feeling bad, peeing more often, my weight has been going up and down and I'm the heaviest area in weight I've ever been. I've been getting nauseous way more than normal. Also have been getting cramps and have been in so much pain and have not been able to sleep much and when I do finally get to sleep it's either not good sleep or I end up waking up. I have also been way moody as if I'm on my period but even more moody, also have been getting hot and cold flashes. And I have that small thought in my head that I could be pregnant but at the same time I don't think I am I keep telling myself to wait and see if I get my period but i shouldn't be getting it until like the end of October. I also don't wanna buy a pregnancy test and it come back negative or end up getting my period. I feel as if that would be a waste of money, then again I also want to buy one just to stop that small thought that comes up once in awhile.