I can relate to your situation. For awhile I could not trust anybody because of the toxic work and social environment I was in during the latter days of my days in undergrad which permanently hurt my ability to see only the good in people. I'm still struggling, but after moving back to my hometown I was able to reconnect with friends who I knew I had built trust upon before and a lot of those fears went away. Maybe a change of scenery and some time to yourself to recover from these stressors that make you feel this way might be in order?