Over The Past Few Weeks I've Had Sterotypical Pregnancy Symptoms,

Over the past few weeks I've had sterotypical pregnancy symptoms, but mostly sensitive sore boobs and nausea with occasional vomiting (which is very rare for me) a few weeks ago I had an early "period" which was very light and short. A few days later I tested and got a very faint positive line that disappeared quickly. This month my period came 6 days late (yesterday) and was very crampy and abnormally heavy blood flow. I know there's no way to know for sure but i was wondering if you thought this was a chemical pregnancy/miscarriage or just an abnormal period. I never did test after that one time. If it's thought to be chemical, do I need a rhogam shot?