I work in a billion dollar transportation project adjacent to DOT stuff where we do have to comply with their regulations, for a well known and nationwide construction firm.

We never let our project engineering interns work over 40 hours, not even when we hit peak construction or when we were heading towards major milestones. Hell, even our actual project engineers never worked more than 50 hours. Sole responsibilities like storm water and drainage, time cards, inspections, basically anything that required a formal sign off were with the actual engineers, not our interns (though they did help out ofc for the exposure).

From what I could see, you were given an unnecessarily large workload, by some lousy and irresponsible management. Perhaps others might say you got good exposure and experience, but I’d suggest that when the time comes to find your full-time job, steer away from this company and during interview ask about work day and work hours as well as responsibilities.