I am 5 days late n I feel lik I'm getting my period but then nothing. My bf n I have been ttc for almost 3 yrs now. Any advice?

Pregnancy test. The 1st thing to do when you're late is a pregnancy test. If it's negative, consider asking your dr for a pelvic exam- sometimes, if you have an ectopic or tubal pregnancy, HCG levels will be low enough that the urine test will be negative, but untreated ectopic pregnancy is very dangerous.
Pregnancy test. You should take a pregnancy test - if positive, congratulations. If your test is negative, and you have been trying to conceive for three years, it is time for an infertility work-up and you should see your ob/gyn.