Sleeping Excessively. Feeling Groggy, Dizzy. Xanax Helps. Had A Normal Hearing Test. Am I Okay?

Question: I have a problem with sleeping. Sometimes I will sleep too much. Normally I need about 8 hours to sleep to function properly. Sometimes I will end up sleeping through the alarm and end up sleeping 9+ hours. When this happens I wake up feeling groggy which I think is normal. The problem occurs after the next night (2nd night) of sleep even if I sleep a normal amount of hours (8 or less). I wake up from that second day with a very dizzy/foggy feeling. It feels as though something inside my brain is not working properly. It feels as if the wiring is messed up or there is something wrong with the neurotransmitters. It lasts for about a week and nothing can take it away. I am completely unable to concentrate or study or do anything productive when this happens. The only thing that makes it a little bit better is taking xanax (0.5 mg) on a night which I have a prescription for but don't take too often (once or twice a week for anxiety on average). I have had a late sleeping schedule for the past few years. I usually sleep around 3 am and wake up around 11 am. I have had an mri done on my brain which came out normal. I also had a sleep study done which came out normal although I slept about 7 hours during the study and couldn't oversleep during it. I've seen an ENT and had a hearing test which came out normal as well. I don't usually oversleep but since I don't have to get up for work in the morning time it just happens sometimes and I am very frustrated as to what is wrong with me and what is going on inside my head that makes me so messed up for days related to one night of sleeping too much. I don't find anything on the internet or anyone who has my problem.

Thank you for the answer and advice. I was wondering if you think coffea cruda-30 would be good to take before bedtime?