Hi, I'm An 18 Y/o Female And A Few Days

Hi, I'm an 18 y/o female and a few days ago I went in to my Gyn to have an iud. (Mirena) I wasn't on my period, but due to the fact that I was leaving the state before my period came my doctor agreed to do the procedure. The attempt to insert it was painfully unsuccessful through many tries, the tool would go into my uterus, but the mirena applicator would not, so my she gave up and I went home. Now, I just got what I think is my period, but it is 4 days early. Is this my period and if it is, why is it early? By the way, I haven't had sex since my last period in July.