r/pokertheory

Not a big sample size but recently got into poker again and found a huge discrepancy between my winrate at 5nl and 10nl rush on gg. On 5nl, my winrate is around 20bb/100 (1600 hands) and on 10nl it is around -0.4bb/100 (1400 hands). Is this expected? Did I move up in stakes too quickly? How much of this good or bad is variance? Can I measure my skill level based on this sample size?