OK, here's what to do.
Go to the TEAM statistic page. See where your team ranks in the pitching statistics for the league. I would guess they'd be in the top third, meaning you really can't do much better without trading away some good prospects.
I would also guess that your offense or fielding is in the bottom third, certainly in the bottom half of the league. There is nothing "wrong" with your pitching, so it must be your offense or defense.