Is my ex depressed? why did he practically disappear off the face of the earth? should i be concerned for him?

my ex and i are both in college...we broke up over a year ago but have rekindled things earlier this year then hooked up when i was home from school...he said then (about 2 months ago now) that he still loved me, yet he treats me like ****....he knew that i was "talking" with a guy when i was home and said that hed be happy for me as long as the guy treated me right...now almost 2 months later that guy is my boyfriend....weve been dating but ever since it was on facebook, my ex has not been on facebook...its like hes avoiding it at all costs..i know this sounds so petty and stupid but its just so strange that he like cut himself off of that social network thing for like a week now, when usually him and so many other ppl are on every day...idk hes been on medication for depression so i just hope hes okay and idk if hes upset that im with a nother guy or what? other people have even made comments about him ignoring their phone calls and "disappearing"