Breathe, you could have been indoors working all day like myself today... ;:;banghead
First off, id say go shoot some clays and/or try patterning your shotgun at 40 yards with a 40-50" circle with a 6" dark circle on center with a few different brands you trust and a couple different chokes you may have; circling your pellet holes after each round. Go back to the basics because nothing replaces confidence and frustration (worrying about missing) like a gun YOU know you can shoot the pimento out of an olive.
I will say that on father's day we had a big trap shoot with the mechanism mounted on a big pull behind trailer with 10 different shotguns (all virgin guns to me). There was a benelli montifeltro with a specific load (clear casing) that i absolutely could not miss with no matter what and after i took a little break and picked up an 870 with a complete different load (red federal shells), I absolutley could not hit Shit if you payed me and i chalked it up to a completely different load and pattern, (maybe even the f.p.s difference..)
It took me at least a half box of shells to find a different aiming point with that particular 870 and it just never did feel anywhere near as natural as the first gun i picked up nor like any of my other shotguns sitting at home. This just made me relate with your frustration in a similar instance and can relate it to a load and choke that was obviously not working for what i was used to.
The 3 different chokes i use (patternmaster, brileys full extended, stock modified) mixed with their own certain loads for both waterfowl and upland definitely have my brain trained.
Hope those beers help kick that frustration clock back a bit :;:cheers
(if you're missing on birds/clays flying straight away from you; try lowering your point of aim/bead 2-4 inches.)