I think its the ASIC miner they just out build the block chain quicker than our slow old CPU can, so they win the race when there are two contenders for the block chain.
If its any consolation I have thousands of coins with from the time when the ASIC minner started with
Status: 0/unconfirmed, not in memory pool

I dont know what happened

Latest stats


{
  "blocks": 15906,
  "currentblockweight": 4000,
  "currentblocktx": 0,
  "difficulty": 21481.59772724999,
  "errors": "",
  "networkhashps": 463693087398.0007,
  "pooledtx": 0,
  "chain": "main"
}