curious11

(I dont think this posted the first time... sorry if it did!)
Ok so my first concern is the fact that my brother has MS. As far as I know it has not been determined to be a genetic disease? so I dont know the likelyhood of me also having it. However, here are the symptoms I am dealing with... at first I thought I was showing signs of arthritis. I was waking up at night with excruciating pains in my knees. When I sit for too long in one postion my knees hurt. And over all, my joints just feel achy! However, when I posted on an arthritis board, someone said it sounded more like a nerve problem to them... so MS is what popped into my head. Now... i'm 20 years old, at 17 I had a baby. During my pregnancy I experience numbness in my leg due to the babys position the sciatic nerve. However about a year ago I had this happen again. Obviously I was still not pregnant, but my leg was numb for over a month. I knew this was not good, but I did not seek medical attention due to fear I guess. It ended up going away. However for the past 6 months I have been dealing with some other issues. When I walk for more than a few minutes, my left knee begins to stiffen up, and I begin to almost drag my leg, or trip over myself. This goes away if I sit for a minute, but quickly comes back after a few minutes of walking. In the morning when I wake up, my legs are very trembley. When I lay in bed at night/ in the morning and stretch my legs begin to shake uncontrolably until I stop stretching. Also I noticed that one night when I went dancing, by the end of the night I couldnt even stand because my legs were shaking so much. I had to sit before I left so they could rest. I dont know what any of this means, I was hoping someone could tell me if they have experienced anything like this, and if not, maybe thats good, because maybe this isnt onset of MS!