Yeah, I never understood why a business would need more than 2 interviews tops to decide if you are suitable. Work portfolio would have been checked out before first interview and then would just be personality fit/meet team after that.
Sorry to hear about your situation dude. There are some good tips from everyone here. Maybe try getting a better work/life balance going on. Come in to work later and leave earlier, 12 hours on anything can be draining. Hopefully that improves things for you.