Cycle

So I'm TTC I gave up on tracking, but I've been keeping up with my periods. I've noticed that for the past couple of months my cycle has been coming on every 1-2 weeks. I'll stop bleeding one week 2 weeks later I'll start bleeding again. This month my period ended on the 6th and started back on the 15th. This is the 2nd month this has happened. What could this be? Im normally have regular periods, but not lately.