weird symptoms I've never had, but BFN

I'm 30 and Trying to conceive baby #1. I also have PCOS and this is my first month TTC. I'm taking prenatal vitamins and Metformin, but have been experiencing some weird symptoms I've never experienced before.

I am VERY emotional the past 2 weeks. I tear up over the weirdest things: movies that aren't sad, random songs (also not necessarily sad), nature, couples holding hands. This never has happened to me before. I also have been having mild cramps but my period isn't due till next week and I never get cramps with my period. Also experiencing random nausea from certain smells and foods that never bothered me before and from riding in vehicles or slight plane turbulance. My nipples and only my nipples are SUPER sore and almost always at attention.

I took a pregnancy test but it was negative. I did take it a week before I'm supposed to have my period. Are these weird side effects from taking prenatal vitamins or could I be pregnant and it's just not detecting on the test yet? please advise. My body has never acted like this before.