How to manage depression caused by OCD medications?

Hi doctor,

I have been suffering from emotional and thought contamination OCD for over 30 years. I have been on Asentra (Zoloft) for a year now. My symptoms have weakened by 70 to 80 % since I took 200 mg. The problem is that when I am on Serotonin medication, I develop depression. I am tired all the time. I had difficulties making myself go to sleep for months, and I could hardly motivate myself to do anything. I cannot focus for more than 10 minutes when writing or reading, and I feel tired. I develop zits on my face and cannot stop picking at them. So, my skin looks terrible. I develop depression, and out of despair, I eat too much food. I am not supposed to, and I gain a lot of weight. In eight months, I gained approximately 59 lbs. I have been taking two kinds of pills for high blood pressure for two months, and my blood pressure still never comes close to 140 mmHg. It is usually around 160 mmHg, often up to 180 to 190 mmHg. For diabetes, I take Metformin. It is not as effective as it was years ago. My depression also gets worse in cold months. Without pills, I cannot function at all because OCD takes over my life completely. But with the depression and weight gain, I have to deal with very high blood pressure, high cholesterol, high blood sugar (diabetes 2), insulin resistance, skin problems, cravings, etc. I had the same problems years ago when I was on Asentra before. My psychiatrist does not want to change my medications because they really help with my OCD. To tell the truth, I am scared of changing them as well. I do not want my OCD to get worse again. I have had so many bad life experiences that I feel capable of reliving them again through ERP since all my triggers are connected to people who have caused suffering in my life. I would be thankful for any suggestions or advice.