Why do I keep spotting weeks after my menstrual cycle?

My period is irregular, but I had it in the start of this month. normally my period would last 3 - 5 days however lately for the past couple months i'd have them longer. and this month it was the same but since i stopped flowing i've been spotting on and off and sometimes getting blood clots. i'm a little worried, because i'm overweight and it is possible it's a health problem. i can not go see my OB/GYN at the moment because my mothers insurance stopped covering me because i wasnt a full time college student. so if anyone with a medical background can shed some light onto the situation, it'd be appreciated. thanks.