I'm just really lonely
Why do you think that you are so lonely?
I'm just really lonely because I have no one.
While it is okay to feel alone, it is okay not to want to be alone and find somebody for yourself. It would make you feel better so that you don't feel alone anymore.
I can't find someone so it's understandable that I'm lonely. Besides I just like being alone.
If you want to find a partner, just keep looking! You should only seek out a partner if that is what you really want though.