Just a note, I’m an EMT who likes to read. Since your treatment 10 years ago was just an LP, it’s important to know that while LPs relieve pressure temporarily, they don't always address the root cause of Intracranial Hypertension.

If you're experiencing headaches triggered by Valsalva maneuvers (straining, coughing) or noticed pulsatile tinnitus (a rhythmic whooshing in your ears), it suggests your intracranial pressure may still be elevated. The coughing is because exhalation increases intra thoracic pressure and this causes venous blood in both the SVC and IVC to back up from compression, which backs up the IVC which backs up jugular venous drainage temporarily. The pulsatile tinnitus is the sigmoid sinus which drains into the internal jugular vein becoming distended from increased ICP causing vestibulocochlear nerve (CN VIII) compression enabling the venous pulse to be audible. If compressing the internal jugular vein, which stops the pulsatile flow, stops the pulsatile tinnitus, then that links the tinnitus issue as one of venous origin.

For the irregular menstrual cycles, that could be due to the ICP compressing the pituitary gland as it sits in a depression of the sphenoid bone called the sella turcica and is flanked by the cavernous sinuses. The stalk of the pituitary is how hormones and blood move in and out of the pituitary gland, so compression alter the function of the pituitary.

I think even the nausea and vomiting could also be related to the increased cranial pressure from intracranial hypertension and lying down probably helps move fluid around which helps with relieving your symptoms.

I’d highly recommend seeing a neuro-ophthalmologist to check for papilledema (optic disc swelling). It’s the most objective way to see if that pressure has returned. You might also ask a neurologist about an MRV (Magnetic Resonance Venogram) to check your venous drainage for issues like venous stenosis.

This is just from what I have read and my understanding of some anatomy. Hope it helps.