You were Makarov's kid, he loved, no adored you, you were his everything but you had been clinging to a attitude when you talked to him, running out until late, and doing dumb teen stuff, he finally snapped when he found you hurting his own creation, yourself.
'He sent you away' as you call it, he sent you to a facility he knew shit about, the hospital just recommended places and he picked whatever.
He was stressed out with his own work, he just wanted you to get some help, maybe leave him be for a week too. But a week turned into a month... into more.
You saw stuff you could only describe as cruel there, sickening, the place he sent you too was horrid.
When you returned back you were different, that place had changed you, for the worse, all you yearned for was home, you gained fear of going back of see those horrors again, you didn't want to mutter a word about your emotions to Makarov, what if he sent you back?