My period is three days late &I had sex alot of times last month &this month. I'm having pregnancy symptoms but I took a test &it said neg. What now?

Repeat. It isn't for sure negative until 2 weeks after last mensrual period because of varaibility of the date of ovulation. You have to have enough HCG to make the test turn. A blood test might be more sensitive and if you are pregnant, your test could turn positive before 2 weeks after 1st day of missed perioe.
Recheck. Recheck your pregnancy test if your period does not come with in 7 days. First Response brand -good option. Other option, get a blood test in the doctor's office, HCG test. Blood test is most accurate. If you are using contraception, great. If not, then your chances of pregnancy are higher (whether sex once or many times). Should talk to your doc about your goals,birth control vs family planning.
Retest... Repeat the pregnancy test in 1 week if your period doesn't start. At that point, you may wish to see a GYN to discuss your irregular periods if it remains negative. Are you trying to conceive? If not (and you aren't pregnant), make an appointment anyway to discuss reliable forms of birth control.