Poker can be brutal sometimes. You can play near perfect and just be in a groove where you're holding the 2nd nuts far too often, or not getting paid when you do hit hands. I'm sure you know that, so it's really hard to quantify how much bad variance someone is adsorbing.
That being said, you have leaks. If you're playing optimally, you can absorb a decent amount of variance. Keep in mind, on a site like Bovada where people will gamble more, you're susceptible to more swings since people will get their money in more often, but they still have equity. And when you hit pockets when that equity is being realized more than it should it can cause some serious frustration.
A couple of suggestions:
1) Shorten your sessions. Don't play really long sessions, especially at zone.
2) Don't play zone. Focus on other games for awhile where you can get reads.
3) Continue to work on your game and focus on a couple of your biggest leaks and really dedicate yourself to banging them out.
4) Work on tilt, and subtle tilt. Make sure you're checking in w/ yourself and being a good quitter when sessions don't go your way.
5) Consider getting a coach. If you play another 300k hands w/o really knowing what you're doing wrong, vs hiring someone who can likely make good adjustments, and you play that 300k hands better, the coaching will pay for itself many times over.
Based on your graphs you're probably absorbing some, but not that much. It's just play that needs to be corrected.
You're welcome to join our free study group as well. Talking and sweating other players is a great way to re-think your approach and learn:
Polished Poker Vol. I Study Group