Did I screw myself?

I've experimented with SR a little over a week now I dropped a methadone habit of 70-90mg a day and stopped cold turkey. I did preload and it's taken about 200-300mg of sr to even keep me on my feet. I haven't had any in two days and I bought a tonnnnn of it so I used it as a "test run" however I'm getting methadone tomorrow and after researching more and I should have to begin with im reading it won't even work??

Is this true?? Will it not even take my withdrawal away. I'm panicking and tomorrow can't come fast enough to prove this theory. It's my fault and I accept responsibility I should have dug harder and tapered more until I was really ready to get off. I'm not as concerned about feeling euphoria or anything but if I take the methadone will I at least not be in withdrawl? Will it reduce some of my
Pain? I've been in so much pain the last week and a half it's been crazy.

I don't know what I should do I'm so scared and so upset. I'm happy for SR but so scared I have done myself in