Talk to Gynecologist on Frequent Spotting Post Delivery

Aoa dr, I have delivered my baby via Vbac on 7th of november & I bled for almost 50 days postpartum while my baby was exclusively breastfed. After about 60 days post delivery my first period came (very light bleeding/spotting for 7 days) & that was during the time when I introduced formula as well (only 1 or 2 bottles per day) Now the problem is ever since then I am having my period every 15 days (although very light spotting type) and some spotting in between those periods as well especially whn I walk a lot. My baby is on combination feed (only 1 or 2 bottles of formula per day). Pls give opinion If it is normal or anything to worry about or get checked? Thanks!