Want to make the switch from heroin to suboxone..need help now?

I have been doing about 6 bags of heroin a day for the last 3 months, prior to that i was taking 2 mgs of subxone 2 times a day, but i messed up and relapsed...the last time i tried to stop i waited about 16 hours from the last dose of heroin, i took 8 mg of suboxone and felt nothing, i still felt sick and i dont know what im doing wrong..when i used to take 2 mg of the sub i felt great all day, energized and ready to go. now even when i take the full 8mg i still feel like crap, am i not waiting long enough? anybody that has been through this please help..i am 23 years old with a 2 year old daughter and i need to get healthy..i also can not afford to keep wasting my subs as they are really expensive..anybody with advice please let me know..thanks so much