Pushoff problem

OK, My strongest part of the 100m last year used to be my first step, the push off from the blocks…
Now It’s exactly the opposite, I am showing some good technique and top speed running, but I get out of the blocks like a 400m sprinter, meaning there is no visible push, it looks like I am only trying to get in the running position fast and not driving out with power.

Can you really lose a skill that fast ? only 2 months ago I was getting Wow’s about my first step, I broke 30m PR’s and now it’s gone… The only thing I changed in the routine was going from deadlifts and half squats to full squats with much lower weight, I also EMS’ed my rear chain and didn’t touch the quads at all.
Oh and I stopped with the plyos to get ready for season.

So, should I start doing those heavy half squats and DL’s again to regain control over my quads ? I really lost a few inches on my thigh because of those full squats.