This probably isn't much help. But when I came off cerazette I had a normal period, then the next one was nearly a week early, very very heavy with clots and only lasted 48 hours. My next one was normal, just a couple of days early but I'm convinced the 48 hour one was a chemical pregnancy but have no way of knowing for sure x
Ive just had a chemical, it was only slightly heavier then a normal period (which are pretty heavy) and lasted 8 days instead of 5/6. I got a positive test up untill the last day of bleeding. Tbh I would rather have not known and put it down to a dodgy period. Not sure if this helps at all.
Wouldn't have thought there was any difference in how you manage it. Most of them happen without you knowing anyway don't they. Its only early testing that causes people to pick them up. Hope you feel better soon x