I don't know what's going on! Help?

Ok so I had regular 5 day periods, 28 day cycles, not too heavy. Pretty normal. Had a normal cycle in November. Then i Didn't bleed at all in December. 8 day period in the beginning of January. And I only lightly spotted at the end of February for not even a day, like it was only there when I wiped, once. And nothing since. I get small cramps like once a week or so. Currently TTC but haven't had any luck. I've taken numerous pregnancy tests and they all come out negative. I don't have health insurance currently so I can't go to the doctor. Anyone else have had something similar happen?? I don't know what's going on and just looking opinions or advise.