Some of the games you play, like Castles of Burgundy and Azul, rely far more on skill than luck, so your ELO would appear to be a fairly accurate reflection of your current ability.
When you first start playing any game on here, your ELO climbs quickly whenever you win, because a K muliplier is used, which is bigger for those who have played fewer games. (This also means that your ELO will drop by a lot when you lose.)
Maybe you had a couple of somewhat lucky victories early on that boosted your ELO beyond its 'correct' resting level?
You also say that you often play with people of 150+ ELO higher than yuors. In many BGA games, there is a pretty big difference in skill between someone of just over 100 ELO and someone in the high 200s, so maybe you should limit your play to opponents who are apprentices/regular players for a while. Your ELO will increaase by less when you win, but you should win a bit more often, so it would be less depressing.
Or if it's really making you miserable, just play in training/friendly mode, where your ELO won't change at all.
