<human>: So my girlfriend broke up with me after we had been dating for about 3 and a half months because her previous boyfriend cheated on her and she didn't want to feel vulnerable again, I get that. What killed me about that was how out of the blue it was. So she asked me back out, confessed she loved me, and now our relationship is pretty healthy I'd say. However she has a friend that is a boy, who I get extremely jealous of when they hang out. Because of the distance between us, I see her about once every week or two weeks because I don't have a car. However, her friend that is a boy does have a car and they hang out about 3 - 4 times as much as me and her do. Is this crushing jealousy I feel because of my insecurity about the relationship, or because she is hanging out with another boy, or simply because I am jealous that someone gets to see her way more than me? Part of me feels like I am just looking for an excuse to end it because of the pain she had caused me, even though I am consciously aware of how miserable that would make me. I know it's irrational, I know it's messed up, but every single time she tells me they're hanging out I get completely overwhelmed with this feeling of anger and jealousy that I have never felt before. Recently my brother moved to California (I live in Maryland), and I am starting to think that his leaving, along with one of my friends getting engaged and the other in a serious relationship, I am just plain lonely and the jealous feelings are tied to the isolation I am going through on account of my entire social group scattering all at once. I am trying to find out how to stop this really depressing mindset I've been in recently, but there is no clear solution. I don't want to take things out on my girlfriend, but this crushing loneliness and irrational jealousy is causing me to edge towards a breaking point and I can't do anything to stop it.

Condense the text into a few key points
<bot>: – My whole social group of friends and some family dissolved at once and I am afraid my lonely jealousy is putting too much strain on my slightly shaky relationship.