I am never late on my periods. I am on a 23, 24 days cycle. I had unprotected sex three weeks ago. I am now four days late. Went and got a pregnancy blood test and it came out negative. If I'm not pregnant, then why is going on?
The doc says for me to go back in two weeks if I still hadn't had my period. I am a person with very low patience, this is driving me crazy.

What's going on? You are ONLY 4 days late. 100% of women will be at least that late numerous times without being pregnant from their first period until the end of menopause. Many without even having had sex. You have another 10 days before it is time to take a test. I'm not surprised it was negative.

You have to learn patience... you have to wait to test again like your doctor said... and you have roughly 9 months to wait if you are. Not to mention untold other reasons. That's the reality of life. It runs you, you don't run it.

Periods can sometimes be off, even if it hasn't happened before. If it happens, there has to be a first time, right?

If you are trying to become pregnant, a lack of a period when expected would certainly make pregnancy the first thought.

Give it a bit more time, and if still no period, you can always try another test.