If it was mine I'd start by ditching the sea foam... then I'd ditch the Fram filter. My preference is FleetGuard filters but Wix or even Baldwin will do. Donaldson is also a very good filter. Second thing... I'd make a point of using a DIESEL RATED, heavy duty engine oil in either 10W30 or 15W40 grades depending on your present ambient temperature range. That alone should build oil pressure and a good HD oil will have sufficient detergents to keep the engine clean.
You may have a combination of a bad filter or just a blocked filter after the seafoam has loosened a bunch of crap up........ but really 55-60 is where the pressure should be on a tight bottom end of a 172 engine.