I wouldn't be so hard on yourself! Missing out on the 4x gain that ETH had (it's only 2x from your buy in now) is very nice, but not nearly as awesome as many other coins had! If you managed to be 2x ahead of where you were back then, then you're still as good as if you had held on to ETH.
I've been steadily holding my ETH since august but truthfully I don't feel like it has done so awesome, compared to some other investments!
Congrats on that USDT+BTC -> STEEM conversion!! Very nice.. what's that, 3-4x gains? That must've made up for a lot of losses :)
You win some, you lose some!