I don't know how your contact with him has been in the past, but if every time you've been together you've had a serious, full-blown session then he might be feeling pressure that if he sees/calls you it has to be a long, many-hour thing that he just doesn't have the energy for. The next time you talk to him it might do you well to say that you might like maybe just a text or quick email from him now and then because you're wondering how he's doing; or ask him if it's alright for you to do the same and just send him a quick word. Sometimes just one quick word or sentence that lets you know you're thought of can get a person through an entire day, and it might help him to know that you are there for him during this difficult time, if he should choose to want your attention.

Also, in my experience, it's common for a sub to feel very needy during the beginning of a relationship, so don't feel bad about that, just remember that you have a mind to go along with your emotions and use your brain to help you through it. Your Dom's family difficulties has terrible timing and I feel sorry for both of you, I hope everything turns out alright.