It's always a bad idea to combine depressants. You being fine last time doesn't matter much.
There also is a big difference between 2 beers+10 mg of Oxycodone & 3 beers+ 20 mg of Oxycodone which are the possibilities of combination with the ranges that you wrote. On the top of all, there's Clonazepam which is a potent depressant as well.
Finally, I don't think that anybody can certainly guess how this will turn out because there are so many other variables like your tolerance, weight, the time frame of consumption, ...
You may be fine taking all of what you listed one day, you may die choking on your own vomit after having a couple beers+ 10mg Oxy+ Clonazepam; so just be careful, have another person with you, have food in your stomach, don't attack it like you've never seen it or will never see it again. It's a good idea to keep the doses lower than you are used to using separately when you combine 2 or more depressants which is valid for combining multiple stimulants as well.
Sorry for being a party pooping depressive person and have fun.