OP, I really feel for you. It's is absolutely horrible to feel this way. I always had lovely skin until after ds was born and then, over the course of a couple of years, the acne got worse and worse until it stopped me leaving the house. My face was covered; I felt disfigured.
My GP started me on lymecycline. Didn't work. Changed my pill. Didn't work. More lymecycline. Didn't work. Lush products, LRP, Simple (utter shit as you now know!), Liz Earle, tea tree oil, antibiotic cream, cleansers, toners, exfoliators. I even spent a fortune on some vile Chinese medicine stuff that turned my skin orange and didn't do a thing for the spots. Diet, no alcohol, exercise, everything. Spent hundreds and hundreds of pounds on stuff that made absolutely no bloody difference at all. I was caked in makeup from dawn to dusk and I was completely paranoid about the way I looked.
I was just about to go back to the GP to beg him for a roaccutane prescription (despite my brother having suffered severe depression whilst on it) but was googling and found acne.org. Honestly it changed my life, no exaggeration! They recommend benzoyl peroxide which seems drastic at first but I used it religiously and within a few weeks my skin was completely clear. The thing that's really important though is the advice about how to handle your skin. No over-cleansing, no exfoliation AT ALL.
I used the cetaphil cleanser and moisturiser along with the benzoyl peroxide for about a year. That was about 4 years ago. I now oil cleanse with jojoba or coconut oil and bung on some benzoyl peroxide around totm. Nothing else (a bit of Astral in winter, maybe).
I get the odd whitehead by my nose at totm and that's it. I'm now 41 and my skin is genuinely lovely 
Oil cleansing sounds mad but if you do it with the right oil (jojoba!) it's the best thing you will ever do for your skin. Cetaphil is good to rebalance but after a while you won't even need that. I know I sound a bit mad and evangelical but that's because it really did work when I thought I was stuck with painful, ugly spots forever.
If nothing else, have a look at the acne.org site - they are selling their own branded stuff but you don't have to buy it, everything they recommend is also available in boots tbh. The advice is amazing though. Best of luck.