I have taken 3 pregnancy test it the last 12 days one 12 days ago and 2 today all were negative. I have at least 7 signs that I'm pregnant (sore breast, light headed, headaches,cramps,side aches,bigger breast, back aches.) I'm 3 days late for my period, and I had unprotected sex 2 to 3 weeks ago

Three days late is way too early to test. I'm not surprised that you're getting negative results on a test. At three days late you're not even considered to be late.

Wait at least another 2 weeks. If you don't get your period then test using first morning urine. If that test is negative then wait until your next period is due. If you miss it, test again or see your doctor for a blood test.

Wasting your money on tests, it is far to early, You need to be 10 days to 2 weeks late to even consider testing and even then at times a false negative is possible.

When you test, do it first thing in the morning with first urine of the day.

It is also too early to really be getting any pregnancy signs