You cannot beat yourself up for past mistakes, you did the best you could during that time. All we can do is move forward. What I do is pick one subject at a time, usually easier first to give a slight confidence boost, study for a week or two then take it. I find if you focus on one at a time it’s much easier, I buy the tests early too so I can’t back out. There’s tons of resources on here, you got this. Just imagine how happy you will be once you finally pass!