why can't I view my iCloud list in Mail any more?

Mail stopped working. Took HOURS to reset it. Now I can get and receive email, but the list for what I had on iCloud disappeared. How do I get it back? I seriously can't keep up with all the wonky things that happen regularly since I installed Yosemite which is THE. WORST. THING. EVER. I wish I was getting paid for the DAYS I have wasted tinkering to fix tech issues in the past months! HELP, please!