Advice

I'm currently not TTC, so i'm not sure if this is a paranoid scare or the actual thing. I'm currently 9 days late on my period (my cycles are somewhat irregular, so this fact doesn't particularly worry me except it's never been this late before). I had protected sex during what was supposed to be my fertile window (pullout & condom). About a week or two ago, I started experiencing constipation (it's less constipation and more feeling like i'm full of gas), a few cramps here and there, an increased appetite (that might just be because I skip lunch every day), constant sickness (nausea & it feels as if i have to vomit often), and body aches. There have been no changes in my breasts. Due to a few of the symptoms I was experiencing, I went to the store and picked up a test a little less than a week ago. I tested negative, but it was a test the was on the cheaper end of the spectrum. I thought that the fact that I recently started taking birth control again (without aligning it to my menstrual cycle) could be delaying ovulation, as well as the current stress I have on my plate. Should I stop taking the pill to test this theory and align it to my period, keep taking it until I hit the placebo pills in my pack, or anything else? What should I do?