Junel fe & no period!?

So my first month of junel fe, my period was normal. My second month was very light almost non-existent. Now my third and fourth months I have had no period! I don't think I'm pregnant since I take my pill religiously and we always use condoms plus I check for holes after each use. My breasts get a little tender right before my placebo week, but then the soreness disappears and I have no period. Is this normal?