Missed period

I've tested a few times everything came back negative except a vvvvvfaint line on a first response 5 days ago. The only things that are making me wonder if I'm pregnant are missed period (2 days), cramps for over a week I keep saying "this is it im going to start my period right now!!!" But nothing is there. Headache since 1dpo. It's dull but it's still there. I have a weird feeling in my stomach and I'm crying easily lol. I'm burping after everything. Have been for 2 weeks. I get super constipated but when I do go it's diarrhea (tmi sorry). I bled little drops of brown blood that was almost unnoticeable for three days (6,7,8dpo) and that's something I've never expierienced. Almost feels like a uti but I don't have one. Lots of sharp cramps at random times. I had toast milk and coffee but my stomach feels sick. Normally if I eat something like that I'm good all morning. Could I be pregnant? When should I test again?