Should I prepare myself for major downswing?

No, youre winnings should now run always above youre expected winnings unless you get unlucky
No need to think about these things after 2.5k hands
Now you got lucky and sometimes you will get unlucky. Upswings and downswings happen to everyone.
If you go all-in AA vs A2 and win the hand your yellow line is still going to drop, eventhough you dominate opponent's cards. It just follows the equity %. Just keep playing/learning!
looks like you had 2 big hands where you were a dog and won and 1 mayor hand where you were a slight favorite and also won. So do not sweat it, luck in the future is not affected by what happened in the past.
Don't expect a major down turn. Your winning will continue to live on. Any unlucky moments will not result on a major down turn.