Why do I lose more than I win?


If you're higher rated than your opponent, then of course scoring 50% (one win and one loss) will result in a net loss of points. If you're the lower rated player you'll gain points.

Interestingly, whether you're the higher rated player or lower rated player, losing first and winning 2nd results in a better outcome than the opposite... although it's only noticeable for players close together in rating (within about 100 points) and the difference is only ~1 rating point.
The same (losing more points than winning with same opponent) happens even when the opponent is closely matched in rank. So I'm not sure about the point system here.

The same (losing more points than winning with same opponent) happens even when the opponent is closely matched in rank. So I'm not sure about the point system here.
The site uses the Glicko rating system.
https://support.chess.com/article/210-how-do-ratings-work-on-chess-com