I tend to agree with you that you may be over-worrying and obsessing about whatever this is, but I definitely think it's worth checking out to make sure nothing's up with you, psychiatrically or neurologically.

Please get in to see a psychiatrist or neurologist and let one of the docs begin to diagnose you and then refer you to the other specialist. You need to be looked at from both perspectives, and of course you'll need to tell them both about your weed history and history of any other drugs you've taken. They'll also want to know about your family history of neurological/psychiatric illnesses.

If I were the doc, and mind you, I'm only a first-year med student beginning on Monday, but if I were the doc, I think I might order an MRI or CT scan to see if you had any physical abnormalities with your brain, particularly in the back part/bottom of your head, where the cerebellum, which governs balance, is. I'd also order an EEG to rule out some type of electrical (seizure) disorder.

No one can ever truly diagnose a perfect stranger over the Web, and as well-intentioned as the previous posters and I are, you need to take any guesses submitted here with a grain of salt and actually start with a real, board-certified in-person doctor of your own if you want an accurate diagnosis. Hope you feel better soon! And I hope you have health insurance, too.