Raise more hands, be more aggressive, learn not to stack off with tp and the like. You go to showdown 27% of the time and only win 48% of them; this is much too low.

Yeah your sb stats are purty bad. I'm not sure what you're doing because your vpip fromt he sb isn't abnormally high by any means. You must be completing with lukewarm hands like KT and playing for stacks when a K hits, or something of the like. I think you should filter for hands in the sb/going to showdown and losing.

Post some hands. Filter "Went to showdown and lost." You can ask if you're stacking off when you should. Losing after 1k hands could be variance, losing after 10k hands can even be some bad bad variance, but losing after 35k hands needs some re-evaluation and you need to change your play. I don't think you're ready for 50nl yet.