it WAS only two months...he IS just out of rehab...and you WERE starting to get a bit clingy. in the future, keep the relationship between you and the other person, NOT his mother. said gently, this isn't about YOU for him....his mood, his backing off, his whatever....we aren't so powerful as to wreck somebody else's recovery.
quit listening thru the grapevine for updates, respectfully draw down the amount of contact you have with his folks, put it down, let it go.