I am 20 years old; my periods have always been irregular...usually my period starts a little later than the month before (usually around 4 to 7 days late in worst case scenario). I usually keep track of my cycles and when I'm ovulating because I haven't made the time to get with the gynecologist to get back on birth control since I stopped dating a guy who had a vasectomy. I'm a little over a year overdue to have a papsmear. So my current stress is that two weeks ago I had unprotected sex with a guy which was one week before my scheduled period was supposed to start. I was a little stressed out about it, but I did know my ovulation cycle had been done and over with by two weeks or so as my ovulation calendar had told me based off of my previous period. I am now 15 days late for my period to have started, and 4 days ago I took a home pregnancy test in the evening and it came out negative, then one the next morning right when I got up which came up negative again, and then again this morning which also came up negative. Of course pregnancy is a concern because I'm not ready to have children yet, and my period still has not started. I have looked online at different forums all over the web and some stories of people and pregnancy tests (like they took 7 home pregnancy tests and had a blood test that all came up negative and then found out they were pregnant after finally having an ultrasound). Is that common to happen? Should I be worried about having 3 false negatives on my home pregnancy tests when I took them at almost 2 weeks after when my period should have started? And if I'm not pregnant, should I be worried about hormonal imbalances, thyroid problems?
-Background on my current mental and physical state....the day after I had sex this month, I came down with a stomach virus...I lost 4-5lbs and currently weight 96lbs (which isn't very drastic, because I'm a petite person)
-I've been applying for college, going through some financial changes, and some stress at my job
-I eat on a regular basis.....drink plenty of fluids (maybe a little excessive on the caffeine lately)
So, in you expert opinion...what should I do? Should I be stressed about my period being 15 days late? Is this normal?
I'm very stressed about all this. Please get back to me soon.