Go right down in weight - as in the Mehdi Starting Strength program - go down to a ridiculously low weight, and gradually go up each session.
You can keep up your leg work - and your ego, if necessary - by doing heavy leg presses &/or dead-lifts, but with this squat routine, you'll learn to get it right.
When I first started (without any trainer's instruction), I got my legs reasonably well developed (at least to my own, low, standards), using leg presses, and other machine exercises, but I was never really comfortable with squats. I thought I would need some sort of "yoke" to keep the bar in place.
Anyway, many years later, taking up lifting again, but without a gym, squats were my only leg option. I struggled like you did for quite a while, but since I have done the "Starting Strenght" program (which says to start off squatting an empty bar - I didn't go that far), my form has improved automatically, and I don't have a problem placing the bar now (I'm up to 5 sets of 5 reps with 98kg on the bar, as of today).