On miningspeed it says "It takes 120 confirmations before balance is shown!" I would have expected there were more than 120 confirmations since the first block I've been paid for (oldest one paid) ... my "Paid" value has been increasing, but the balance is still 0. Is there somewhere where I can check the number of remaining confirmations for the balance?
If you are getting enough (more than 0.1 ZEN) to get paid every block your balance will never increase because you get paid directly on your wallet. Balance is for when your earnings on the block is not enough to receive a payout, for example you get 0.01 ZEN every block, your balance will slowly go up and when you exceed 0.1 ZEN, you get paid

Yes, I've been getting more than 0.1 per block. Miningspeed is down at the moment (what gives?) but a while ago I had quite a few ZEN. However, zen-cli getinfo shows balance 0 and also "errors": "WARNING: check your network connection, 0 blocks received in the last 4 hours (96 expected)"
{
"version": 2000852,
"protocolversion": 170002,
"walletversion": 60000,
"balance": 0.00000000,
"blocks": 0,
"timeoffset": 0,
"connections": 0,
"proxy": "",
"difficulty": 1,
"testnet": false,
"keypoololdest": 1496223843,
"keypoolsize": 101,
"paytxfee": 0.00000000,
"relayfee": 0.00000100,
"errors": "WARNING: check your network connection, 0 blocks received in the last 4 hours (96 expected)"
}
zend has been running as daemon. What in the world is going on with this coin? Did I just lose a day of mining?
You don't see your transactions because the wallet is out of sync. Try to add these nodes to your zen.conf file:
For those who have ZEN addresses with me, I've just updated the spreadsheets with the current balances: