POTS spell and headache

MY heart rate just jumped from 61 bpm to 121 bpm and my tinnitus got louder, just from being on the floor.. i was looking for the back on an earring. I was probably down there for 5 minutes, good resting heart rate. And then I went to sit up.. i didn't even stand up. I went from being on the floor to sitting up, and i doubled my heart rate and got dizzy. 

I started getting a minor headache. 

I have a feeling some of my headaches, or many of my headaches are not neurological, but have to do with blood flow. I think it's a good idea for me to get an MRI of my neck. My neurologist and my rheumatologist both want to see an MRI of my neck. 

I have a feeling the instability in my neck, the fact that the Xray showed that it was straight and partially reversed, because of the instability in my body, has a lot to do with my headaches.