opinions on possible pregnancy and canceling my surgery

I had unprotected sex on the days that this app says I was most fertile. I start my period in 8 days.. I just downloaded the app two days ago and put my information in and had no idea I was most fertile during the time of intercourse (which was last week) and I am uneducated of the times women are most fertile. I have been experiencing  nausea, headaches, back pain, my moods are all over the place, diarrhea, I feel like my sense of smell is heightened and last night my breasts were really sore. These symptoms happen at different times, not all at once. However, I am prescribed vyvanse and had just gotten the prescription refilled after not taking it for a while and when I first started taking it, it made me sick, some headaches, and it messes with my mood. I also have bipolar disorder and I'm on lamictal to regulate my moods, but forgot to take the medicine for a few days, possibly a week or a little over. I have taken multiple pregnancy tests but they came back negative. I am scheduled to have my wisdom teeth taken out Friday (in severe pain) and have read you shouldn't have them taken out during early stages of pregnancy because that is when the baby is developing fastest (so the article said). I have also been under a great amount of stress.. I need opinions on if you think There's a chance I am pregnant, if it's just the meds, or the stress, and if I should cancel my surgery?