Awww, sounds like it was rough for both of you. A times for babies that are 5 months are usually 2 to 2.25 hours long and the first A time of the day is usually the shortest, so I think he's OT from that first A time on. Try putting him down after 2 hours of A time then and see if that helps.
Also, is he not fed between 8 and 2 or is that a typo? I'd try for not more than 2.25 hrs of A time in any block of EASY, and aim to have him fed and in bed asleep by 8, so he's got a 12 hr day/night. If he's not tired by then I'd move the catnap up or limit it to 45 minutes if his other naps were decent.
HTH!