Squat and press is not increasing on SS.

[nathlee1992]

Hi,
I have been doing SS for 8 workouts, I have been training for about 8 months, before SS I did some split program.
Anyway I started SS about 3 weeks ago and here is my lift stats(kgs):
Squat: 3 sets of 70*5(I actually felt bad at the first few workout so I decided to use 70 kg to train the form a little bit until I feel normal, I figured out I felt I used my lower back more at the first few workout, so my squat actually start progress from 70kg on my 6th workout, although I still feel quite a bit on my lower back muscle.)
Press: 3 sets of 35*5
Deadlift: 1 set of 60*5
BP: 3 sets of58.5*5
Clean(Hang): 5 sets of Bar*3 (Learning the movement for 2-3 workout)
8workouts later

Squat: 75*5, 75*5, 75*3
Press: 40*5, 40*3, 40*4 (Really struggle on this lift)
Deadlift: 1 set of 100*5
BP: 3 sets of 62.5*5
Power clean: 5 sets of 30*3

My squat and press is not increasing that much..... did I start too heavy? I got the book and I think I am using a decent form(I got the book and I read a few times on squat and press)...
I repeat my press and squat weight for 2 workout but I just can't get through it, should I deload the weight to 60kg for squat and 30 kg for press?
Any advice will be really appropriate.... thank you.

[Brodie Butland]

You definitely started the squat too high--likely the press as well. This is shown by the fact that both lifts have only increased by 5kg over 8 workouts.

Reset both and start linear progression over.

How do you know that you are using decent form? Are you videotaping? If not, I'll also bet there's a form issue at play.