What is i thought he liked me but now he avoids me?

There could be various reasons why someone starts avoiding someone they previously seemed interested in, such as:

1. They may have found someone else they are more interested in.
2. They could be going through a tough time and need some space.
3. They may have realized they were sending mixed signals and do not want to lead the other person on.
4. They could have taken something the other person said or did the wrong way and now feel uncomfortable around them.

In any case, if someone is avoiding you, it's best to give them space and not to push or pressure them to explain their behavior. It's important to accept the reality that they may not feel the same way about you anymore and to focus on taking care of yourself.