###Human: I had my period late by 21 days. Lower left side pain, bloated on that side; and back pain, abdomen pain. ###Assistant: Hi. I suggest you get beta hCG (human chorionic gonadotropin) test to rule out pregnancy and ectopic pregnancy with 100 % confidence. If negative, you should consider taking progesterone for withdrawal bleed and painkiller for pain. If beta hCG is positive, you need to go to the emergency room as there is a chance of ectopic pregnancy.