Anxiety with fluctuating pulse and blood pressure. Why?

Hello doctor,

Three months ago, I visited psychiatrists and psychotherapists for advice concerning the depression episodes I periodically have, including bad mood, unwillingness to do anything, and obtrusive negative thoughts. When I came back, I was not in depression. The doctor prescribed me Fluanxol 1 mg daily. I was not told to avoid drinking alcohol, and it took quite a lot during one month. Then one day, I felt worse. I had apathy, it was challenging to do something, even to wash my face, it was difficult to concentrate, I did not have an appetite, and I was losing weight. It lasted about three weeks when a horrible feeling of anxiety appeared. I went to the psychiatrist, who said to stop taking Fluanxol and prescribed me another pill to be taken in seven days after stopping taking Fluanxol. Up to this time, I had taken Fluanxol for 79 days. But anxiety did not stop, and in two days, I could not resist it. I was trembling and sweating, and the feeling was as if my heart was going to jump out of my breast. I could neither eat, nor drink, nor sleep. I was taken to the hospital, where I have prescribed Diazepam 10 mg and Mirtazapine 15 mg. Diazepam did not help at all, so I stopped taking it. Now I have been taking Mirtazapine for 13 days. I still have anxiety, and my pulse is constantly changing from 90 to 115 beats per minute. My blood pressure is changing too, but it is not very high (up to 124/90 mm Hg). I sleep about 5 hours every night (earlier, I have never had problems with my sleep) and sweat a lot during the night. I cannot do anything because of the weakness, and when I do something, my heart rate goes higher. My hands and legs are trembling and sweating. Sometimes I feel a little better, but not for long. Sometimes I feel nausea and temperature 37 Celcius. Yesterday I took a pill of Lexotonil, and it helped me from anxiety for that day, but I still had tachycardia. My question is whether taking Fluanxol not being in a depression episode and together with alcohol provoked serotonin syndrome. I have never had before neither such horrible anxiety nor panic attacks. My doctor told me to increase the dose up to 22.5 mg for better sleep, but I am afraid that it can worsen my condition if I have serotonin syndrome in a mild form.

Thank you doctor,

No, I do not consume alcohol now for more than a month. I drank just to relax. Sometimes in large quantities (two bottles of wine or even more). When I found out that it is not compatible with antidepressants, I stopped consuming it. And I did not drink every day, maybe every week. I smoke electronic cigarettes. It seems to be relaxing too. I am under constant stress because of the COVID-19, quarantine, and temporary unemployment. I do not have any problems at home. When I visited a psychiatrist, I did not feel depressed, but I worried about possible depression episodes to come. Now I am afraid to have serotonin syndrome because of taking Fluanxol, not being in a depression episode, and consuming alcohol. Can it last for several weeks in the mild form gradually progressing?