I don't understand myself one minute I'm okay the next I'm all sad and crying. I don't like people I like locking myself in my room. I feel like no body understands how I feel. am I okay?

You seem to be a very introvert person, it’s ok to go through stages like this. You will get better in time and just know you are not alone.

I went through the exact same thing, particularly when I began college. I came to the same realization you did, that I prefer to be alone in my room than socialize. To answer your question, "am I okay", there is absolutely nothing wrong with staying to yourself. It is perfectly fine to do this, which is what introverts are. I am definitely introverted because I cannot socialize with more than 2 people at a time, so group gatherings or parties are not for me. As long as you think you are okay and don't experience any negative emotions (and if this style of life benefits you), you are okay! However, if you start to experience sadness or depression from locking yourself in your room, perhaps this would be an indicator to seek higher help.