I did a little research on the spaces, and they are not tumors, and can be related to certain types of cysts or other disorders, or be what is called an incidental finding (which is a very... frustrating finding, been there, done that).
So, get the MRI and the doc should get at least one follow up to make sure that there is no change. With that it can establish that the finding is not the cause for your symptoms.
Headaches are a weird thing - and migraines can vary (my mom had her arm hurt) and they can be visual or do all sort of crazy things, so you have to evaluate carefully what is what - that being said you have to know what is the source and know if the headache is the reason or a symptom. It is not always clear, and it may take time to know.
I think you need to ask for an mri with contrast to relieve any lingering questions in your mind.
If you've had an MRI and you have normal eyesight and the doctor hasn't said you've got a tumour and nothing has shown up on the scan, I think its fair to say you don't have one. If you did have one, the MRI would have shown it and the doctor would have said straight away so you could sort out treatment. But if you're still worried, go and see your doctor again
Would also like to add that I saw the eye doctor a day before the normal mri and everything with my eyes, including pressure, were normal