Not necessarily sometimes you have to let nature take its course. Stress can cause your cycle to be late or early. If your test is negative most likely you aren't pregnant. Most pregnancy test can...
After intercourse sometimes mine just swells a little, but doesn't tear. I wouldn't say it is normal, but anything is possible you should contact your doctor to see if something could actually be...
Your cycle could just be irregular especially if u were on birth control prior. If the pregnancy test states its negative then most likely you are NOT pregnant