Weight gain

Trischa
Hello Ladies,
I am a FTM so I'm not really sure if this is normal and instead of asking friends who wouldn't know, id rather ask here where everyone has either gone through pregnancy or currently is (congrats either way!)
At the beginning of my pregnancy I weighed around 112 lbs which was a normal weight for me (I'm only 5ft.)
I'm currently 7 weeks and 2 days and two weeks ago my doctor prescribed me Progesterone (200mg, 2x a day) and within those two weeks I have gained ten additional pounds. I am unsure of it's the medication or I need to change my diet or whatever. I just feel like I'm gaining weight too quickly and too early.
Any and all thoughts would be greatly appreciated as I'm sure you understand that this has me worried.
Thanks for reading and best of luck to everyone!