Heres my 2p. I was in a similar situation to yourself, working full time and struggling to get my head around. I took me around 10 months to sit 6 exams, lots of pressure in work, tiredness, etc and with time starting to run out I panicked! I eventually decided to go part time as things were moving just too slow. Finally after going part time, I could see a major progress, although I sat my last sitting in my 18th month and with all the pressure I was under I managed to pass all 14 exams with 90+% average.
So from my experience, If you're struggling with moving forward and understanding the subjects, take more time off and you will defo see an improvement. Good luck, its all doable..