I'm stupid

Also feel like I’m stupid. Was on the phone with tech support the other day and was unable to talk clearly and using the wrong words and going blank many times. Luckily the person was patient and understanding. I used to have good memory but this too is deteriorating. Also think someone in my body trying to harm me like their underneath my skin. They cause the physical feeling of going brain dead. I’m becoming slowly poisoned inside out. help.

Sounds like you need to spend some time with a patient doctor. It takes time to get on top of this illness. Try not to get carried away with unrealistic ideas. Find the parts of yourself that you like and empower them.