How can you tell if you had a miscarriage if you didnt know your pregnant?

Im 18 years old. Ive been on the pill for a little under 3 years now. Ive only had one sex partner, but we have intercourse frequently. This month, my period came very early. Its very slow, which is not normal for me. Also, ive had excessive cramps, which i never have. Is it possibly a miscarriage? Or am i just jumping to conclusions? Please help me.

If you just were bleeding you'd have a positive test still if it were a miscarriage.

Most likely you are jumping to conclusions. This sounds just like a period (not a miscarriage), just one that is "abnormal". Let it pass and everything should be fine. Consult a doctor if your period doesn't go away within a week, or is like this every month.

I had a miscarriage and i didn't know i was pregnant at the time ( i was 16)I had excruciating pain in my stomach. It felt like someone was ringing my insides out.I then went to the toilet and gushed blood everywhere, i then heard a plop in the toilet and saw what looked like a huge blood clot but was my placenta dropping into the toilet. i didn't realize what happened until i went to the doctor and explained and then she examined me and said i just had a miscarriage.i then bled for the next 4 days...i think you may be overreacting and are experiencing nasty period cramps. But if you're not sure i would go see a doctor.