Period/breastfeeding question… please advise?

I am still breastfeeding my almost 2 year old on occasion. So I know that can cause cycle irregularities. However despite this I’ve always had a regular period. The last few months I’ve been spotting between periods. My period ended on the 27th and today I am bleeding again like a period. Is this due to still breastfeeding and just a hormonal imbalance? Or could be something more sinister? I made an OBGYN appointment in 3 weeks.