Does anyone have any insight?

Hi guys. So basically, on the 26th of December, I was at work and started experiencing heart palpitations and dizziness. I didn't think much of it until it kept happening into the night and the next morning. These mild symptoms had over the next few days grown into more concerning symptoms such as weakness/numbness in my left arm and in my legs, along with muscle spasms, headaches behind my eyes, chest pressure/shortness of breath, vision changes, globus sensation in my throat sometimes, and yesterday, I started experiencing severe lower back pain that would shoot down my leg when I tried to walk. Please keep in mind that I'm an 18-year-old girl. Prior to yesterday, I had been to the ER a few times concerned that there was something wrong with my heart, but 3 EKGS showed that I was fine. I even saw a cardiologist who ordered an echo and 48-hour Holter monitor, all of which came back great. I've also had a lot of bloodwork done, that shows my TSH levels were normal, the proteins in my heart 9(like troponin and d-dimer) were at normal levels; every part of my blood they tested so far was normal. I spoke to my doctor who said I should now see a neurologist to rule out something like MS. I saw the neurologist on Friday and he told me that my variety of symptoms doesn't really make sense with an MS diagnosis but that he's been surprised before, so he ordered a MRI and EEG (which I'm still in the process of scheduling.) My doctor prescribed me 100mg of Gabapentin for the muscle spasms which has helped, and then for the new back pain she prescribed me 15mg of Meloxicam which worked for a little bit but after I woke up this morning the pain came back. Instead of shooting down my leg like before though, it radiates to my hips and the right side of my pelvic bone. I went to urgent care today and she told me that I really should get an MRI done to check for MS, but I have no idea how long that's going to take to be able to get an appointment. I'm honestly just really scared. I don't think I'm in any immediate danger (mostly because all of the ER doctors I've seen have told me so) but I don't want to be in pain anymore and I don't want the numbness/weakness to get worse or cause more permanent damage. Nobody in my life understands me either, I've been fighting with my mom so much lately because she's certain there's nothing wrong with me. Things are just really tense. I'm also home for school as I'm online for my college, meanwhile everyone is away doing their own things and keeping busy. I just feel like I'm going crazy. I'm not saying that I want there to be something seriously wrong with me, I just want to know what's wrong so I can do whatever it takes to fix it.