How do I know that I am suffering from a brain tumor?

The pain you feel could be caused by stress, not enough sleep, or even dehydration. Try to drink water, lie down in a calm place, and massage your temples gently. If it doesn’t go away or gets worse than before please consult with your doctor immediately.

Head pain lasting a month requires proper medical evaluation.
Specs can't cure it.

There is no medical condition specifically referred to as a "sleep stroke." However, strokes can occur at any time, including during sleep. A stroke happens when blood flow to the brain is disrupted, either due to a blocked blood vessel (ischemic stroke) or bleeding in the brain (hemorrhagic stroke). The risk factors for stroke include hypertension, diabetes, smoking, and other cardiovascular conditions. If someone experiences symptoms like sudden numbness, confusion, trouble speaking, or severe headache, even during sleep, immediate medical attention is crucial.

Having symptoms like muscle twitches, tingling in your hands and feet, leg weakness, ankle pain, and difficulty speaking could indicate a nerve disorder. Abnormal EMG and NCS test results suggest nerve problems, possibly due to conditions like peripheral neuropathy or nerve injury. It's important to follow up with your doctor for further tests and treatment, which may include specialized tests, medications, or physical therapy, depending on the cause.

The blurry vision and the difficulty in focusing can be the vertigo that the ear fluid causes. It is common and it does not mean that you have a brain tumor. The ear fluid can mess up your balance and vision. Usually, it gets better on its own, but you might need medicine or special exercises if the problem keeps bothering you. 

It is not very likely to get intracranial high blood pressure from a single 200mg dose of doxycycline. Intracranial high blood pressure is an uncommon side effect that may lead to headaches, changes in vision, and nausea. Adequate hydration can help in its prevention. Don’t forget to follow your provider’s instructions when taking this medicine and inform them about any worries you might have.