I feel for you. I hope it wasn't as bad today as you thought it might be.
Stop often if you need to, stay warm, and try to have fun. On my tour in June, I stopped on the second day because of torrential rain. I kept singing "Singing in the Rain" then changed all the words to fit my biking in the rain. It worked until I stopped for lunch and got too cold to go on.

Have a fun time regardless of the weather!