> there are times I drink too much and forget what happened the night before
That's bad.
You may not be able to reduce your alcohol consumption. Not everyone can. But...
> I only ever drink on a weekend and not throughout the week.
That's a good sign. So what's happening here is that alcohol lowers your inhibitions. When you're sober, you have control over yourself, which is why you can get through the week. When you start drinking, you lose that control, so you keep drinking, and you pass out. Whether you can drink without crossing that threshold is an open question. Like I said, not everyone can do that. For some people, one drink pushes them over the edge.
Do this experiment: next weekend, don't drink at all.
If you can do that, then the FOLLOWING weekend have ONE drink and STOP. (That's one drink for the WHOLE WEEKEND. Not one drink on Friday and another on Saturday.)
If that works out OK, then the NEXT weekend, have two and then stop. Not all at once. Pace yourself. At least an hour between drinks. If that works out OK, then the NEXT weekend go up to three.
If at any time you find yourself thinking, "This is all OK, I can have one more" then STOP. That's the danger sign.
If at any stage in this process you find yourself making excuses for why it's OK short-circuit any step in the process, then I have bad news for you: you're an alcoholic, and if you don't want to keep blacking out you're going to have to just stop.
UPDATE: raztogt21 also had some very good advice: never drink alone. It also helps to let your drinking buddies know that you're on this program so that they can help keep an eye on you. If your friends ever encourage you to drink past your limit, get new friends.