Your doctor will probably tell you not to drive, but they can't take away your licence. Should they have ample reason to believe that you are a threat to others and yourself, they do have the ability to notify the DMV, and recommend that your driving privileges be temporarily suspended.
Your symptoms seem consistent with HPPD. (I am not a medical professional)
There have been annecdotal reports of mushrooms bringing relief to people, as well as exacerbating some cases of HPPD.
What's your relationship with your doctor like? Just be truthful and mention that you're having alterations in your visions. That'll usually be enough to get authorization to get an MRI. The MRI won't find anything related to HPPD, as no actual structural damage had occurred, but it can help put your mind at rest by ruling out any immediate life altering diseases. CT scans won't show anything either (kind of regret getting one, but somehow managed to delude myself into thinking I suffered a stroke due to the whole Panic attack out of fucking no where, aphasia, head pressure, adrenaline induced shaking, stiff neck, and giant black sperm floating across my central vision, still waiting for those radiation powers to kick in/). ""
Is your doctor aware of your history of substance-use? Moreover, do you have any reason to think that your doctor will discriminate against you should you divulge your substance use? If you just describe your symptoms, you may be able to get an MRI, but your doctor may also go down the rabbit-hole and order a whole bunch of tests as well to exclude any other treatable disease that display similar symptoms. Don't downplay the severity of your symptoms, you'll just end up being frustrated (and there will be plenty of that to go around as you try to get treatment for a disease that is an orphan disease/not many doctors and even some mental health professionals are not aware of). You may also have to be a bit more proactive in your advocacy, and look to find those open minded and intelligent doctors who would be willing to help you in your journey of recovery. I certainly had to change my PCP. And after all that you may find that a lot of people on these forums will probably be better informed on HPPD than most doctors are.