Is that how people are

So, today I graduated from my Masters degree. There were so many people to support their families. My parents are away and so I had my baby and husband. During my degree, I have taught each and everything about science and lab research. I felt she’s like a friend. After I had my baby, I started writing my thesis and I didn’t go to school much. She’s gotten into few programs because my boss is the one running those programs. Today, she’s standing few feet away from me and she didn’t say anything.?this goes for both of my undergrads. They didn’t mind me. My friends or at least that’s what I thought, whom I have helped studying, finishing assignments, reminded them about deadlines and they left me and went with their families. No one had any time to take pics with me or even introduce. I tried calling them and no one responded. Honestly, my nature is to help anyone who needs help and I’m sensitive, attached. I don’t know whom to trust anymore. I don’t know if I should be cautious about people. What I felt today made me to think should I even help anyone or should I even make friends? What did I do to deserve this. i don’t know what to do anymore