Furnace Issues

The furnace has suddenly started making a high pitched whine and running constantly instead of the usual on and off thing. I doesn't sound good. I'm having a guy come to look at it on Friday, so hopefully the news won't be too bad. Fortunately we have one of those service plans with our gas company that covers most furnace issues. The furnace is in the middle of my husband's workshop which is a complete mess right now. Maybe I'll be able to convince him to clean it up a little before the repairman comes. Anyway, with overnight lows in the single digits predicted for the end of the week, I sure hope it doesn't completely quit working!!