Depressed and my boyfriend doesn't care

I've struggled with anxiety/depression on and off since middle school (I'm 18 now) and I finally got up the courage to tell my boyfriend (on and off for 3 years, long distance) about it. He knew about my anxiety, but not about my depression and suicidal thoughts. I've had a really, really hard week with a lot of stress that's going to continue for months to come so I finally broke down and told him about it. He tried to help a little and then just didn't say anything. He didn't reply to my texts for hours today (for no reason) and never called me like he normally does at night even though he's not doing anything. He just told me sorry and that's it.. I thought I could rely on him to at least try to comfort me but I guess I can't.. I really don't know what to do, I'm angry and sad at the same time. I don't expect him to be there for me every minute of the day but I thought he'd try to at least help out a little bit.. Any advice?