METFORMIN WHILE ON DIANE 35.

Teya
Hi everyone. My name is Teya. 28 yrs old. My bf and i have been together for 2 years now. I have been recently diagnosed with PCOS. (May 9) after a miscarriage at May 2 at 5 weeks. My doctor put me on folic acid and metformin 500mg 3x a day. i have lost 17lbs since starting metformin. Today, (june 5) was my follow up check up. She put me on Diane 35 to regulate my period. I understand that it can cause weight gain. I am a lil confused why i was put into a weight gaining And weight losing meds. (I am aware metformin is not a weight lost meds but i do lose weight while on it). Anyone on the same boat?