I have a condition called idiopathic intracranial hypertension. I was diagnosed 4 years ago. I was receiving treatment from a dr. and eye dr. I had one spinal tap to relieve fluid. I was on a prescribed diuretic and pain medication. I lost my insurance from a divorce. I filed bancruptsy on the hospital for my medical bills and my family dr. dismissed me as a patient because I filed on the hospital. Now I have no insurance, no doctor, no prescription medication, and no money. I am a single mother of 2 children, one has autism and disabilities. I am in pain, and need relief, I want to try an over the counter diuretic to try to control the excess fluid building up on my brain, but don't want to make the condition worse. Many add lots of herbs and supplements that I worry might make it worse. What OTC diuretic would you recommend? Please help

Go to the ER - this is nothing to address over the counter.

I am so sorry you are going through this terrible time.

NO ONE is going to suggest that you try to deal with this OTC.
What you need to be doing is getting health benefits, so tell us where you live. Not all subsidized care is made easy to find, depending on locale.
For instance my state has a plan that I never see mentioned anywhere, and I rarely meet anyone who has ever heard about it. I guess it's deliberate, I don't know.
You also need to write to the manufacturer of the medication, because a lot of them will give you coupons for free or low cost drugs. Doctors will give away their samples, which they have closets full of - if you can afford one visit. Call around and ask at the desk.
I take hydrochlorothyazide, a very common diuretic, and my drugstore has a plan for hundreds of drugs for $5/mo.
But you need ongoing care first and foremost. FIND that plan, that sliding scale clinic, or just go to a walk in clinic and tell them your financial situation.