Idk if this happened to anyone before but last month af came on time (28 day cycle), and I had what…

Idk if this happened to anyone before but last month af came on time (28 day cycle), and I had what I thought was implantation bleed in the second week (very light pink spotting...one episode) but the following week (an entire five days before my af was due) my period came and it was very painful and heavy. I mean I’m over it but the sudden switch in my cycle since losing our baby really threw me for a loop. So now I’m wondering if I had intercourse on the correct days since technically I’m not sure if my cycle is now back to 28 days or less...