Tldr: So me and this guy are in love. And even though we're in the honey moon phase I can't get rid of the nagging thought that I'm not enough, that I can't give him enough or what he needs. My dad texted and that triggered me so now thia toxic thinking pattern is at the forefront. 
How should I handle this? Becuase my usual coping skills aren't working as well as usual. I want to get better not just for me, but for him as well.

A little backstory. I'm 20 and he's 18. His parents are extremely homophobic but he's leaving in the fall for college. We live about 30 minutes away from eachother (yay for Alabama) and I really can't shake the feeling that I'm not enough and/or not worth it. I've been able to cope in past relationships but I didn't have the distance challenege nor the extremly strict and homophobic parents. I knownthat being Bi doesn't make you more likely to cheat and while I'm always worried about that it isn't really the main issue. I'm more worried that he'll find another guy closer or find a girl he'd be able to spend more tine with and who would be less trouble. I've veen doing well at managing these thoughts but my dad texted today, which really triggered me. I've since blocked him and deleted the message but it did make me think about how he and my mother both left me for easier or better things. Now It's like the voice that usually whispers doubts is screaming at me. And what's worse I can't even talk to him about it because of his fucking parents.