brown discharge, cramps, vomiting, nausea, headache, tired

Either my period is just weird this cycle, or im anywhere between 2-3 weeks pregnant. I don't usually have this brown discharge which I'm reading seems to be common a few days before and after periods, which my period is due tomorrow. I woke up a couple of nights ago early morning feeling very nauseated with not so normal cramping with a headache so bad I wanted to cry. Ended up vomiting within 15 minutes and then back to bed with just some stomach discomfort and the headache. I've also been unusually tired for the last couple of weeks. Headaches seem like I can't make them go away, I'd say I get one almost every day. Also last week (or the week before, I didn't think it was a big deal and don't really remember) I randomly for only 1 day had the brown discharge, which I've now had for 2-3 days. The end of August I just moved back with my boyfriend, and of course we were really hot and heavy the last couple days of August and first week of September. I'm on the pill, but we never use condoms. I really didn't think anything of it until 2 nights ago I had an intensely real dream about giving birth to a baby girl, so real I could still feel her laying on my chest when I woke up. Now I'm a little worried it could be pregnancy instead of my period, but I may just be worried for nothing. Also, I'm a pretty small girl only about 102 lbs 5'6 so I already do have trouble with my periods. Any advice or comments would be fantastic!