So, what's the bottom-line of your post?
One thing that stands out to me (and i may be wrong) is you saw some pretty big contracts, and estimated them based on you doing all the work- no problem other than what we think we can handle isn't always accurate. So in turn you came in way under what the other guys were doing the work for. I'm no going to throw the term "lowballing" out there because i think it's an ignorant term used to frequently but in essence you are doing the work cheaper. But, it does seem like you focused on the numbers and didn't anticipate for expenses.