Shivering and panicking for normal tasks

I sometimes get nervous while doing some simple tasks like say 1. pouring water from the jug. I shiver a lot. 2. when I have multiple things to study for an exam, I start studying for one thing, then I start worrying about the other. As a result I leave what I have started with and move to the other and end up doing nothing. 3. When I walk for some distance, after some time my legs shiver for around say 15 mins. And it is absolutely not in my control. 4. Many times when I am walking up stairs, when I try to walk up fast I lose control on my legs and unable to walk up fast. Takes a lot of focus to get my legs to move in coordination. There is no such problem while walking down. I am very fast and comfortable. 5. I am unable to focus on my studies. I am losing focus while reading every 5 mins.