Welcome to the board! Sorry that you have found yourself here but am sure that you can find some help with your pain issues here.
I'm sorry that you have so much going on right now medically and that the doctors are able to help you resolve the problems so that you can start feeling a lot better.
One thing that I read that concerns me is that you took an extra oxycontin above what you are prescribed. Oxycontin is a long acting pain medication , which means that it should help with the constant pain levels ( base level pain that is there all of the time). You should never, ever take more than what you are prescribed, for several reasons, the first one being that you can accidentally overdose by doing that. Another reason is that most doctors prescribe a certain amount of medications like oxycontin for a set time frame. If you are given 90 tablets of oxycontin , and are supposed to take them one tablet, three times a day, this amount should last you for 30 calendar days. If you take more than you are supposed to, you will run out before the 30 days is up, which can and most likely will get you dismissed from further pain care. If you think that you are in withdrawal, you must contact your prescribing doctor and ask them for direction about what you should do. Never, ever take more than you are prescribed of any medication, but especially when it comes to pain medications without the permission of your doctor.
When I have been on prednisone for various medical problems before, I was always told to take all of the doses at once- are you sure that you are supposed to take it 10 mg /4 times a day? You may want to confirm that with your doctor as well. Just to make sure.
if you believe that you are experiencing withdrawal, your doctor may decide to make slight adjustments in your medication to ease those symptoms. I hope that you are feeling better this morning but please, do call your doctor and find out what he would recommend. It may be withdrawal or it may be that with the chron's disease, there is something that is interfering with absorption of the meds.