Mini pill help ?? Progesrone only pill

Iv been struggling to concieve for 2 years i had 2 miscarriages last year last one was in December.

Dr has put me on the pill for 3 months then stop see if it helps my body concieve supposable this has worked for a percentage of women.

Anyway question is does it cause increased disharge and backpain i only started it last thursday and iv been having a load of white and clear stretchy cervical mucus and my backs in bits?