I assume that he is six months old, from the bottom part of your post, is that right?
How many naps does he have during the day? Maybe he is UT?
I got a lot of help from the NAPS forum and what helped me a lot is to lower my expectations, take it more EASY! My LO is much younger than yours, but don't stress yourself over it.
If you have a feeling that he is OT and not UT, then if I were you I'd bring the E time forward, keep A time short and with little stimulation and then try to put him for nap.
Good Luck!