Abby, I'm sorry you are struggling.
It sounds like you are hoding a grudge against the people from uni because they didn't "guess" that you were struggling then.
It could be they didn't know if you didn't discuss it directly with them.
It might be interesting to explore what it is you wanted from them at that time.
It might also be interesting to explore what happens that begins the need for you to push others away. What is happening? What are you feeling? What fears are arising?

You don't want to be lonely. I'm wondering if you could participate in some group activities (church, community, etc) to have people around you that you could learn to trust at your own pace. Also if you might want to see if a therapist could help you sort out what happens that causes the process of making friends derail for you.