8mg of buprenorphine is easily equivalent to a over a hundred milligrams of hydrocodone in analgesic action (ceiling and inaccurate conversion at high doses withstanding) so it is no surprise you felt a little better.
I pretty much did this exact thing. I didn't want to be on my meds anymore, so I scheduled an appt. with a Dr. certified to dispense suboxone, stopped my meds a couple days before, went in, explained the situation thoroughly, and got a script, no problem.
The crazy old fucker still calls in refills once a month even though i don't take it anymore. It helped alot.