Late month cycle was 5 days early and lasted 4 days, was unprotected sexually active two days after end of cycle and now next cycle is 2 weeks late, 3 negative pregnancy tests. can i get pregnant right after cycle?

Can certainly be impregnated 2 days after menstruation, however pregnancy test should be accurate 2 weeks after missed menstrual period. Pregnancy test checks for elevated urinary gonadotropin levels. This would almost certainly show up if positive at this stage

If you did the tests correctly, you are unlikely to be pregnant. If you have any doubt, get a blood test for HCG level.