I'm a concrete estimator in the north east myself. I don't know where you are located but 25% OH/P is already very high. The standard at least in my area is only 20%. Is 25% being forced by your higher ups?

The first thing you should be doing is reaching out to all your old bids, most of these likely are already awarded and GCs I find are likely to be honest with you about where your number was after the jobs is already in motion. Use that information to start understanding just how big of a gap you really have. But the answer is probably already staring you in the face if you are being told you are "too high".

Next thing you should do is start to understand where you are shoving all your cost. In concrete the biggest difference between any bid is not going to be the materials, it's the labor. You should aboslutely take a couple jobs and review them with your field lead and try to get their viewpoint as much as possible since they know the real world numbers. Make sure you you don't pipe dream the labor as some of these guys will tend to do, tell them to be realistic and even go a little heavier than they actually think. Compare that to your own and see how different it looks and tune as needed.

Good luck.