Anti-anxiety / depressant help

After struggling with anxiety and depression for years I’ve decided that I’m going to talk to my dr about getting on medication for it. One thing I’m kind of worried about is gaining weight. I have a history of eating disorder and body dystrophia plus issues with my body so I’m a bit scared to trigger that again. Obviously I know being mentally healthy is number one priority over weight gain but I have SIBO as well so losing weight is scary bc I can’t really lose it once I gain it. Does anyone have any information/ advice ? I know that different medications work differently for different people but insight helps