What Causes Vaginal Spotting With No Regular Period?

Yes Hi, I was just wondering, well i haven't gotten a full period since october and I didn't get my period in nov, i spotted a little and only lasting a couple of days and i took a pregnancy test and it was neg. so i thought okay then im not pregnant then december rolled around, still no period, spotting again for a couple days only, and it is now january and i spotted a couple days that's it but still no period. i haven't been really stressed out or anything, but was wondering if i was pregnant, it would be my second if i were to be pregnant, so am i pregnant or what should i do? any suggestions?