ONe of the things I thought I would mention is to become familar with the tired signs. It sound slike you are having some good days & its normal to have some bad ones. I use to mistaken Evas tired signs for him being board. Once I was shown what to look for,s ettling him became so much easier but he was a cat napper also so I would get him down & have a max of 40 minutes to have a shower etc.

One thing to remember about settling them though, is once they are crying its too late. You need to get there & settle them before they get to that point. So watch for the grizzles, the clentched fists waving around, rubbing his face etc. As soon as you see anything you think is a sign that he is ready for a sleep, pounce on him. Also, are you wrapping him? If not, you may like to try that. I think it helps alot. Some babies fight it at first so the parent may think they don't like it so give it up. But if you persist with it you will get them settled & sleeping much better I think.
Good Luck & I hope things are improving for you.