Inconsistent Period


So I’ve been experiencing inconsistent periods for the past 2 years going on 3 years now. It just happened out of the blue, I never had issues with my period. But for the past two years my cycle has ranged anywhere between 30-40 days and sometimes skipping months. I’ve talked to a doctor about it and they said anything between 30-40 is normal but it’s the skipping months that is worries me. Also, the flow has been pretty inconsistent as well; some months will be heavy and other months will be super light. Has anyone ever experienced this? 😕