Not sure what's going on....

So I stopped using birth control at the end of November. I have not had a period since. I did take 2 pregnancy tests and both were negative. This past week I've been sick with a nasty cold virus and each morning I have either gagged or vomited slightly. I initially thought it was from all of the sinus drainage. But this morning I woke up out of a dead sleep having to vomit. I also had severe diarrhea (sorry tmi) could this possibly be a sign of pregnancy? Or am I just overthinking it?