Break up or not?

what are signs that someone whose in BCT is breaking up with you if he's got 4 wks. left before he graduates and he's in the OSUT program? You go to see him but he goes with his family instead; sends you a letter stating that he's coming back to you but that he's NOT written in the 3 wks. since you've come back from the trip and you'd normally get a letter either on a tues. or weds. during the week but it all stops? What are some other signs?