i did the same thing. it's been about 4 weeks since i've started up again after 6 years of not touching a club. i would do fine at the range, but on the course i would shank and shank again.
on the course, i was thinking too much. i was thinking "am i swinging right?, i need to get it there; don't miss hit this! "
so now, i tell myself, thinking about your swing is for the range. i get all those questions answered at the range and make sure it gets grooved into my brain. then when i play on the course, i focus mainly on strategy and not so much on mechanics.
just be patient and it will come. i think your range sessions need to be more focused and always done with a purpose or "goal" in mind. ie: pick a flag and hit a whole bucket there.
it's good that your short game was ok, because those are the clubs we use the most in a round.