I have a friend who used subs to kick heroin. He was on the subs for 10 months. He said the withdrawal symptoms lasted for about 10 days - much longer than heroin withdrawal because subs have a longer half life. Withdrawal symptoms not as severe as heroin withdrawal, but still tough to take, especially since they lasted so much longer. 30 days out, he was feeling OK physically but struggling with depression. But he stuck with it, is doing much better now, and tells me that things are getting better every day.
Hang in there! Soon you'll be feeling better too.