Second guessing the spacey feeling...again

I've had the spacey/light headed feeling before....and I remember at the time thinking it was my heart and I got all kinds of tests to show pretty much nothing....besides anxiety. It was a horrible feeling at the time....with pressure around my eyes and feeling like I had to squint a lot. Must've really been a lot of facial tension acting up too.
Well, here I am again. This time, I'm convinced it is a brain tumor. It all started with sinus like issues again. Sinus x Ray was fine. I even saw an ENT and was fine. I started to develop headaches (but I've had headaches before....many times in my 38 years). I also began trying new medicine....Zoloft, then moved to Viibryd. The headaches went away, but I'm left with the floaty feeling. The side effects of the medicine are dizziness, but this is more spacey kind of feeling. Sooooo....I pushed and pushed for my doctor to give me an MRI. I now have it scheduled and have started freaking out. I've had an MRI done about six years ago with no issues. No one thinks I need the MRI, but I can't help but feel if I DONT get it, I Will just constantly THINK about getting it....making myself more crazy.
Anyone do this to themselves? Or anyone has similar issues?