I currently have an Implanon implant but I am not sure whether it's still working. I had no period until about 6 months ago, which is an effect of the drug. Now, I get my period which is erratic and pretty heavy. Sometimes I will get it twice a month.

I believe my period was late this month (as though I could really tell) and was starting to believe I might have been pregnant. One day this week, I got horrible pains in the stomach which I thought was period pain, but they didn't start. When I took a shower, I found a reasonable amount of whitish / clearish mucus with a red / brown spot in the middle. Within a few days, I got my period and it contained large clotted bits.

Was I pregnant and did I miscarry? I have no children and no experience.

Lots of women have miscarriages early on and never know about it. There really isn't anyway to know if you miscarried without a doctor being involved and you still may not know. If you have the same type of painful, heavy period next month I'd contact your doctor and let him/her know that this is becoming bothersome. Sorry about not being able to answer the miscarriage ? but there really is no way. My periods have started the way you described for as long as I can remember.