Utility Worksheet

HI -- I have an excel sheet that tracks utilities for 71 buildings, but it is built quite poorly and I need it summed up on a coversheet -- I assume there is a formula or macro to do this but I haven't been able to figure it out. There is a tab for every month but the layout is inconsistent. Currently backfilling the months from the tabs manually. Need help and advise on this document specifically. Not sure if you do projects this small or not? Let me know. Thanks