Sounds a lot like the sea state you were in loosened up some gunk in the
fuel tank and clogged up the filter, and that once you went through your steps and in flat water it was flowing well enough to restart. The first thing I would recommend is changing the filter. You also need to address the gunk in your
fuel tank. (I haven't had to do that yet, so I'll let more knowledgeable folks address that)
You should always carry a least a couple of extra filters and the tools to change them and bleed the system. Something that should be well practiced in benign conditions, so you're able to do it when the seas are rougher (as that is when it usually is necessary).
Usually whenever you hear the engine start losing revs, the filter is clogging up.