Fishy at best. He probably was involved with the female roommate. Do NOT call him or chase him. He is not chasing or pursuing YOU, and you look desperate if you chase him. Two months is not long enough. It can feel great, sure, but that's just the honeymoon phase. It takes months of being together in many different situations to really get to know someone for real. This guy is not for real. So do yourself a huge favor and don't appear desperate or needy. It ruins self esteem. Just move forward. Don't call him again.