Can this ever be a bad swing? 107k hands...

[soon2bepro]

I've been a winning player NL sh cash for 63k hands, making 3.35 big bets/100 plus rakeback, in various stakes, though mostly NL 100. Before that I was a winning player in limit sh cash, I didn't make more than 1bb/100 plus rakeback over 100k hands, but my skill level was much worse back then as I was just starting.

From then I've started playing in a friends account, and I've only lost and lost, though I know my game has been getting better. In this account I'm now at 107k hands, and I'm -1.71 bb/100. I didn't significantly go up in stakes, even in NL 100 I'm losing a lot (4.11bb/100 over 31k hands)

For quite a while I thought to myself, hey it's just a bad swing, but now I'm starting to doubt it. I know my game has flaws. I often do other stuff while at the tables, sometimes this costs me a pot here and there. Though I've always had that, even more than now also, so it's not like it's new. I can't identify any major flaw or leak that I didn't have before. So maybe the past 63k hands were an upswing, and now I'm seeing that I really suck?

I don't know, many of my friends are high stakes winning players, and though I know my level is beneath them, I more or less break even if I'm facing them in either heads up or in a sh game.

For some reference, my current numbers are 25.53/18.23/2.76. In the past 63k hands they were 29.22/18.26/4.12 (I was calling PF raises with debatable odds, now I tend to fold or rr more often. I was also much more aggressive with marginal hands post flop). If you want more stats just ask.

So, I'm looking for you to tell me if this can be just bad luck, or if I there's no chance I'm a winning player. Or someone tell me to what extent can I adjudicate this to variance and not to better/worse play by me.