Gaining from meds :/

Hello!
My name is Alyssa and I have gone through several medications in the last 6 months. This latest one has caused me to gain over 15 pounds in the last month :(. I'm 5'2" and currently at about 150 pounds. I would love to get back to 120 pounds , although I realize it will be a struggle. I'm 23 years old and in grad school which takes a lot of my time, but since I sold my car, I walk everywhere.

I would love some insight and/or motivation.
Thanks so much!