Its the not knowing what is going on that is the worst. Let the docs rule out as much as they can. A spine MRI sounds like a good next move. If that comes out clean, then you just have to wait for new or worsening symptom to show up and then report them to your doc. Its about all you can do. At some point in time, something will appear that will get you a diagnosis of some kind!
The hardest part right now is not driving yourself nuts with the "what ifs"
It took me 12 years for my MS diagnosis and I swore it had to be something else! Ask for meds that can help relieve some of your symptoms and ....unfortunately.....wait it out. I'm hoping you get the answers you need very soon.