helppp please!!!

Soo i went to the OBGYN to be put on BC... i thought it was a great idea until i found out about the gaining weight part... me for one struggles with holding weight down and it’s hard enough for me to keep it off as it is. i was going to get the thing in my arm “Nexplanon”.. i really need to get on birthcontrol but i’m scared of the weight gain side affects.. any advice on that one or how it affected u..?