I also feel queezy if I take my methadone on an empty stomach but if you managed to keep it down for an hour you should be fine. I have been taking it for 10yrs. and have pretty much felt with everything. So I do know how scary that feels when it happens.
Since it's Sunday afternoon, try calling pharmacist and ask. Since it has such a long half life, you probably won't feel anything. When is your next dose?