H.M.
It could be a chemical pregnancy. We usually have no idea if we have them and they are very common. It could also be stress from TTC. it seemed like when I was TTC everything was worse. It was pry all in my head because I was looking for any symptom every single month to prove I was pregnant. I got pregnant in dec lost that baby at 7 weeks. I got pregnant right away again in March and just had a baby. The first real symptoms I felt both times was cramping and gas. My god did I have gas. On the TTC board it was pretty much the same for everyone. If you got pregnant you got cramps and felt alot like you did when you were going to get AF but the worse thing was that gas! LOL! good luck and I'd test again when your period is one day late assuming you don't get AF. Good luck and baby dust.
Oh and I should add that even with test from Dollar Tree I would get a positive at 10 DPO. So a early result is very likely with todays tests.