Screen glitching

Put the summary of the bug you're having here

*What I expected to happen was my minecraft would run smoothly.
Describe what you thought should happen here

*What actually happened was...My minecraft screen is glitching. It is almost like an x-ray type thing. I can see water and entities through the glitches but I can't control it. It is very random and I don't understand what is happening.
Describe what happened here

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. Log in
3. play