Really, things are this are situations only your doctor is going to be able to have a viable answer to.
If you don't have a medical condtion that can cause menstrual irregularity or abnormal bleeding, it's possible it's just wonky this month. It's pretty normal during the first five years of your cycles to have them be sporadic to a certain degree (though I'd doubt your period "came back" in the way you're suggesting) and now and then afterwards it can happen as well, due to lots of things: high stress levels, changes in eating or exercise patterns, the works.
So, if you haven't had a GYN visit in the past year, now is the time, to make sure it's all okay and not a symptom of something else. But if the last time you had a visit in the last year you got a clean bill of health, unless the bleeding is profuse, will not cease, or is coupled with very bad cramping, it's likely okay to wait it out a few cycles. If this irregularity keeps up over the next couple cycles, put a call in to your GYN.
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