Sad & alone

I have really bad mood swings sometimes and I have anxiety too. At the moment I get really sad when I'm not with my boyfriend. I'll be okay one minute and then the next minute I want to be left alone and I'm sad because I'm not with him. Then I feel lonely and distant. He's quite bad at texting back all the time because he has a lot to do during the evening after school. I could just ring him or whatever but I don't want to be too clingy either. I'm just really sad and lonely right now