Never posted here before but need some advice.

So my boyfriend and I have been trying to get pregnant. Last month (December) we were trying all month all through my ovulation days before and after. I was supposed to have my period starting on Saturday which I did, but I only had it for two days- this is unusual. The blood was light, I probably used two pads and it was red, today I've been having a little bit of brown stuff. I took a pregnancy test before my period and it was negative. Also, all Friday night I had severe diarrhea and vomiting, I couldn't eat anything and I was dizzy at times and felt hot as well. Could these be a sign of pregnancy? I'm going to go home at lunch time to take a test but I'm unsure if taking a test and not using morning pee would be adequate? What do you think?