is he really avoiding me or just not interested?

ok. i am so confused about what to do. my ex bf was in the army and comes from my area. we went to high school together, he found me online back in 2007 while in the army and then we finally met face to face on august 20, 2008, our relationship wasn't that long and we would be in touch pretty much every day. then in october of 2008, he was deployed to korea for 1 year. our relationship was gointg downhill and bang in january he breaks up with me saying he's not ready for a long distance relationship. after our break up i would write him and he answered me. then in november 2009, his base (fort hood) got attacked. i called him and he sounded so happy that i called. he said "thank you so much for calling." then no talking. finally this past christmas, i decided to wish him a merry christmas and welcome home. (he's out of the army and going to the college i went to). he answered me right away. 20 mins later he calls me. and we talked. he even said "it was nice talking to you." and sounded so happy. then into this month i will text him and he answers right away. but now it's been 2 weeks and we haven't said a word to each other. i don't know. i'm assuming he's busy with school work. should i let him go? or should i call him? it's very hard and i do care for him. thanks.