Okay, first off - you won't be sick for 2 days. I've done this before, and you only have to be in mild to moderate withdrawal to start Suboxone from methadone. My old Suboxone doctor made me wait 48 after my last dose of methadone, which means one day of being sick since methadone lasts 24 to 36 hours of that 48 hours. My new suboxone doctor told me to dose today, skip my methadone dose tomorrow, and wait another 8 to 12 hours after the time I would normally dose tomorrow, so I'm not really gonna get that sick at all. I'll be well from my dose this morning until tomorrow morning, so it's actually only gonna be like 8 to 12 hours of being sick. And if you actually take the time between the methadone and suboxone, the suboxone will make you feel better right away. If you don't wait long enough, THAT is when you get sick. The suboxone will push out anything that's blocking your opiate receptors in your brain. So, if you haven't waited long enough, the methadone will still be blocking your opiate receptors, and then you take the Suboxone, and it goes up there and pushes the methadone off the opiate receptors because it is stronger and binds tighter to those opiate receptors. So, once it fights the methadone and pushes it out of the way, there's not enough suboxone left (because it worked so hard against the methadone) to fill the open opiate receptors. THAT is why you get sick. You have to wait, go through mild to moderate withdrawal for a few hours to KNOW that your opiate receptors are open. And trust me, waiting through mild withdrawal is WAY easier, because when you take the Suboxone too soon, you will go through the WORST WITHDRAWAL SYMPTOMS OF YOUR LIFE. And, because the Suboxone binds tighter to the receptors than methadone or heroin or oxy or whatever else, NOTHING YOU TAKE, SHOOT UP, SMOKE, SNORT, OR USE will get that Suboxone out of the way. You just have to wait it out.
So - make sure you wait the amount of time your DOCTOR tells you to before switching from methadone to Suboxone. I reccommend making a Friday your last dose of methadone, skip Saturday and be sick, and start the Suboxone either Saturday NIGHT or Sunday morning, depending on the time frame your doctor gives to between doses.