Negative home pregnancy test, but have all the symptoms?

I'm on the pill, sometimes take it 1-3 hours late. It would have been 3 weeks since we conceived, and I took 2 tests that came out negative. For the last 2 weeks I've been nauseous, have tender breasts, slightly dizzy, weird cramps, have to pee more often,  bloated, all of the works! I dont know if I should try another test or wait and see if my period comes (even though it's not a real period & just withdrawl bleeding from the pill). Could it be too early to tell if pregnant? Even though it's been about 3 weeks?