Help me lose weight

I used to be 140 then April of 2017 I started to gain. Today (12-32-17) I'm about 173. I don't like the way my body looks I want to go back down to 140. I'm 5'5 so either way I'm "overweight" honestly I don't care about that it's just I wish I was my old size again if anyone can help me and give me like exercise planned or good diet tips then I am totally down to listen to whoever. I can see it in my face that I have gained. I used to work out at school we gave block schedule so I used to work out every other day. then second semester hit and I no longer the ability to workout every other day.

old pic

like a week ago

My chubby face now

how my face looked back in March. My boyfriend doesn't have a problem with how I look it's just a personal thing. PLEASE HELP ME GIRLS!!!