Are you playing according to basic SSS charts? Your VPIP is kinda high for basic strategy and your PFR is kinda low. Your aggression factor is low too.
It seems you are playing with scared money. The scenario is like this:
Your premium hand gets beaten, either badbeat or suckout, so you rather limp then raise to lose less money if you don't hit the flop. If you don't hit the flop you check/fold, if you hit it you cbet but get raised and you fold.
Make sure that in head ups if you are a preflop aggressor you make a cbet of 2/3 of the pot. If that is more then half of your stack you go all in. If you check you'll give the opposition opportunity to bluff you out of the pot, even if they hold a trash hand.
I hope you'll take my analysis as an oppinion what might be your leaks. I could be wrong, i am not a coach or expert, but since i play SSS too i know how it is.
Just keep it up, stick to basic SSS for now and watch all the videos about SSS at least 3 time.
It would be good for you to post some hands into SSS section for evaluation.
Just for a comparison my stats:
Vpip: 9.0
Pfr: 8.8
Agg. fact: 6.0
3bet: 7
Fold steal SB: 92
Fold steal BB: 93