How did you know you had MS?

Hello! New to the group, not even sure if this is where I need to be yet. How did you or your doctor know to look for MS? What were your first symptoms? I have been having alarming symptoms, but I'm not sure if MS is the place to start.

Here is everything so far- I have had what I thought were migraines for 10 years, a few days at a time feeling out of it.
-2 years ago this became a constant thing, but mild
-a year and a half ago these symptoms became intense
- no energy, hard to stand for more than a few minutes
- pain and numbness running up and down my arms into my hands, similar feeling in my jaw
- severe pain behind my eye, but only occasionally (every few months)
- constant pressure? In my head, almost like my head is full of water
- heaviness and pain in my feet (feels like if ice was left on too long)
- 6 months ago I began not being able to hold my urine completely, could not make it to the bathroom in time
- heat intolerance, I can not emphasis this enough!
- terrible chills even when it's not hot, but unbearable when it is
- constant low grade headache
- occasional dizziness
- difficulty swallowing
- sometimes hard to talk, feels like my mouth doesn't want to work properly
- hard to remember words or remember what I was trying to say
- I have developed anxiety, had to start taking medication, which is not like me at all
- tonight I had a very hard time keeping my balance

I had a CT scan over a year ago that came back normal, also just recently had my thyroid checked, also normal

My doctor prescribed Gabapentin (due to what she thought was nerve pain and to possibly help my headache's), this has helped tremendously and has brought symptoms down by 85%, but it has become less effective lately.

Is this remotely familiar to anyone? Anything would be helpful, I just want to know which way to push with my doctor. Thank you in advance.