Worried About Period Cycle

As you can tell from the title I'm worried about my period cycle. Last month my "period" was more like blood spotting and it only lasted for like 3-4 days. The last thime I had a real period was at the end of July to like the first day of August. Now its October and I still haven't gotten it. Btw there's no way I could be pregnant, but what should I do?