I've been on both sides of this situation--where one person is just so busy that they don't have time to stop and eat!
When I'm the one who was uber busy, (which was normally the case) my DB was always patient with me. He never made me feel bad for not having the time for him, and what helped for me was to always have some sort of way to communicate with him, whether it was instant messaging, or having a skype video call open--regardless of whether we were talking or not. Normally I would just be doing schoolwork and look up from time to time, as if we were in the room together.
When He's busy, I just try to offer any help that I can. He has had quite a few group projects and papers. For some reason, he always becomes the leader in groups, and has to combine everyone else's work so that it's cohesive. He sometimes has trouble with this because he's dyslexic, so I offer to proofread things for him, and offer my suggestions, since I have a bit of training in this area. I just do whatever I can to help, and I know he appreciates it. I also remind him to have some food, or take a break when I feel like he might need one.
That being said, I do have to agree with some of the other posters, that you are sounding a bit needy. I understand that this is not your intention, but you have to just have faith in your relationship. It certainly does help to know when you'll be seeing each other next, but you can't always depend on this to keep you going. There has to be a mutual understanding of what you want/expect out of the relationship. It seems like it's still a new relationship though, so if you can get through these tough times, then you can get through anything
Just try and keep busy, like others have said. I recommend activities where you gain a sense of accomplishment. I like to challenge myself daily--whether it's applying to 3 jobs instead of 1, or running for 30 minutes instead of 20. It makes it feel like you're not just sitting around waiting for a time when your SO might have time for you. Plus it makes me feel good!