Trouble moving legs and arms?

Over the past week, I've had trouble moving my legs and arms, mainly my hands, and the strength in my hands seems to have gotten weaker. It feels as if my legs actually moving is lagging from when I want them to move. My balance hasn't gotten any worse than it already was. There are moments where my legs will not move at all when I "tell" them to.

When I was 10 (I'm 17 now), I had a brain surgery to remove a tumor that was wrapped around my brain stem. After the surgery, my balance became worse, my hand-eye coordination was impacted a little bit but nothing serious, I couldn't walk on my own for about 5 months, and some other things that I don't think matter in this case. Since then, I've had regular MRI's (I have them every 6 months to a year now), and all my MRI's have come back clean. (My last MRI was June 2014, I'm pretty sure.)

I also think this might be a psychological problem. A few days ago, I watched a video a friend had made about his brother not being able to move his legs since birth and how it's affected his life and his whole family's life. It made me think "How would my life be different if I couldn't walk?", but the problems with my arms and legs have happened before then, just not consistently.

Is this anything serious?