mental health?

I'm in the process of trying to get gastric bypass. I have mental health issues, and was hospitalized in December for medication change as I couldn't see my doctor, because she was booked out tell my appointment. Went to a class last week at the end of May, and they told me that it could affect when I could have it. I took my evaluation and the therapist told me I have nothing to worry about. Someone called me from my surgeons office and they told me to call my insurance company to see. So I did, and they said that it wouldn't affect it. Just got a call from my surgeons office saying I shouldn't of called, and it could still affect of me having the surgery, but I'm confused, because how could it be a negative if I needed to change a medication, and how it could be a bad thing. You would think that your taking a step to make sure your mental health stays on track. I also lost more weight than they had recommended, I had lost ten pounds more than they asked. Does anybody have any insight.