Need Advice

Hi! For context purposes, I’m 19f and have been taking Effexor for maybe three years now. A little less than a month ago, I accidentally took two doses in a day and was hospitalized due to serotonin syndrome. After said event, I get really weird side effects after taking the medicine, some of which are really painful. My pupils get big and my vision blurs, I have trouble communicating with other people and thinking just in general to the point where it affects my work and school, I twitch and I get really terrible headaches that center in the front of my face and eyes. I also feel like I never have to eat or sleep. I didn’t deal with any of this before, and I’m worried that I permanently messed my body up. I know that the answer is “go see a doctor,” but what do I do while I wait for my psychiatrist appointment? Would anyone else have any idea of what might be going on? I’ve never seen this before and I’m just really anxious about it.