Yes, you need this to stop. You can’t expect yourself to function with these episodes happening out of the blue and out of your control. This is serious!
It’s okay to get help when you need it. It’s crucial that you accept help when nothing you already know how to do improves things. You already know something serious is going on. You already know that you can’t handle it on your own. It’s time to get some professional help. Actually, it’s way past time.
My guess is that this is a medical problem, not a psychological one. I may be wrong, but from what described, I think it is likely that there is some undiagnosed medical problem. I don’t have enough information to make even an educated guess. The way to find out is to see your doctor — now! You wrote a clear description of your symptoms. Take your letter with you and share it with your doctor to jump-start your appointment.
If a thorough exam rules out a medical problem, get a referral to a mental health counselor. Even if there is a medical problem, it may be a good idea to see a counselor for the support they can offer. What you are describing could make anyone anxious and scared.
Please follow up and get yourself the help you need and deserve.
I wish you well.