When it rains my downstair ceiling leaks at my baywindow area. It is getting worse and worse and it is moldy . Please help.! I won't be able to have christmas dinner if I don't get it fixed. I have been trying since last year and wasting money.

I would start with the flashing where bay mates to the house, that is a fairly common place to leak. We just had to do a job for a customer when the new roofing installer cut the sidewall flashing and it leaked into the wall. A loose piece of siding may also be allowing water in.