I think that he is not making you a top priority - I hate to be blunt, but that's what it seems to me. Viewing the situation objectively is a good idea. Make plans for your birthday with friends/family...hopefully he will choose to spend more time with you. I recommend you take care of YOU right now and not initiate contact - let him contact you and initiate spending time with you.

Thinking of you - you are young, have tons of life ahead of you...it may not seem like that due to depression, relationship problems, etc. But you sound like a kind, gentle person and you deserve to be respected and loved.