I need advice

So me and my girlfriend (who ill call L) have been together all in all about 6 months, its a long distance relationship but we meet semi regularly by getting the bus. We were dating for 2.5 months but ended up taking a break from eachother for a while because my dog died and i needed to be alone. I regret that. However we got back together and have been together for almost 4 months.

L has some issues. She doesnt eat often, she has cut herself in the past and a few other things which i wont get into. I still love her though, i want to help her. I guess she is scared of hurting me or something? Because thats what she said. She said she was scared of hurting me and basically said things about the relationship youd expect in a break up message. But she doesnt want to break up. Yet she still said she might if she keeps hurting me. Now she said shes gonna be gone for a few hours to like calm down.

Im using this to get advice, i want this relationship to last. I dont know what is happening. Does anyone have any advice?