Movement bug using Unity 5. Please help.

I was having trouble with making a game using Unity 5. A few days ago I had just started my game. I dragged the first person character standard asset into the game. When I moved around everything was fine, although I could only look left and right, not up or down. I did not use Unity again until today. I went into play mode and moved around again. Everything was fine at first, but when I placed the character 5 units above the ground, I got launched into the air whenever I played. Also, the character did not always go in the direction of the button that I pressed. There was another issue which was pretty major. I could look in all directions, which was an improvement, but when I stood next to a wall and looked around, I could see through the wall. I was then teleported outside of the wall. I deleted the character and then put it back in, and this fixed the issue of being teleported, but I could only look left or right again. Please help.