I personally don't worry about synning meds as you only take them briefly and it evens itself out anyway. I have been on cold meds since sunday (weigh in on Thursdays), including cough syrup, lemsip, cough sweets and just resigned myself to a gain tonigh but I actually lost 2.5 lbs. I think that when you're ill your appetite decreases too so it makes up for all the sugary meds.
Just get better quickly and then back on sw, and don't beat yourself up over the meds, you need them! x