What Is This Weird "sound" In My Head

I am looking for information anyone might have related to this very frightening new problem I have. It started one night about a month ago as I tried to go to sleep. I was without ultram that night due to a mistake by the pharmacy. I take this medication on a daily basis. As I tried to fall asleep, I would hear a very loud pop inside my head. I would jump awake, startled. Nothing like this had ever happened before. I concluded that it must be either a reaction to not having my medication, or a myoclonic jerk. I didn't experience the problem again until last week. This time I was sitting at work - not asleep or trying to go to sleep, and I had my medicine - when again I hear a very loud pop inside my head. It was as startling then as it was the first time I experienced it. But this time, when it happened I also felt like an electrical current was running through my body and my vision dimmed. It was all over in a second, but was quite frightening. I decided it must be stress. Despite all my best efforts, it keeps happening on a daily basis. It's never the same time each day. I can't identify a medication that seems to be causing it. I haven't changed anything about my schedule or diet. Now it's beginning to happen multiple times per day. I have a long medical history including hypothyroid, and damage to ureters from past surgeries for endometriosis. I am also having problems with flushing, almost constant low grade fever, numbness and tingling in my hands and feet, profuse sweating for no apparent reason, a need to constantly swallow and headaches. My gp, I feel, is convinced i'm psychotic. I know it sounds bizarre to complain about such unrelated symptoms, but they are happening. I am on the verge of believing my gp must be correct, but thought I might reach out to some medical forums before I go there. I had a similar problem earlier in life with my endometriosis. My doctors had no clue and told me I was crazy. I found great help in an online forum that eventually led me to the top endo doc. In the country. I'm hoping for the same here. Please help.