Is there a crash in the system or what ? That is just disscusting !
The best you can do is check the icloud status page:
When I just checked it the system reported that mail may be "slow or unavailable" at this point and an estimated effect on less than 1% of users, a message posted about an hour after your post here. It does not give any additional information right now. However it seems clear you are likely part of that less than 1%.