My weight loss goals. Any tips?

Okay, I hate this. I have never been in the 200's, but my friends say you can't even tell. I'm 5"7'.

SW: 215
GW#1: 200
GW#2: 185
UGW: 175

I'd actually like to go down to 165, but I'll make 175 my goal, anything under that will be a even greater accomplishment.
My doctor may prescribe me phentermine, which i have previously used and it's very effective, but im trying new strategies. I will take it for 2 months, then take a month off so I keep my diet and don't rely on the pill. Appetite suppressant. I lost 20 lbs with intense workout in 2 months with that pill once to fit into a sweet 16 dress. But that was extreme. Then after a huge breakup, and depression, I gained like +30 lbs. So sad. I'm ready to get my life back on track.