Hoskins, 25 moved to Bramall Lane in January after struggling with injuries since his summer move from Bristol Rovers last year; he scored on his United debut in a victory over Wycombe Wanderers.
He told The Argus: "It's been a bit weird. Brighton is about four hours away from Nottingham, miles away from any family. It's been just me, my partner and two kids.
"I kept getting injured, coming back and getting injured again, which had a massive impact on me mentally. I got depressed and down. I wasn't myself and went to auto pilot when the opportunity arose. I just wanted to get back home."