Did I messed it up..?

My rear wheel has a pretty bad bend sideways and I haven’t really noticed while riding

Take it to a shop. If you don’t have any experience at all truing wheels, and don’t have a stand, unless you’re just trying to tighten a couple obviously loose spokes, you’ll likely make it worse. You really need a truing stand to fix this. It’s usually a logical process of tightening AND loosening spokes on opposite sides while trying to keep the rim round at the same time. If you start simply tightening spokes, you may over tighten them at which point you’ll start breaking spokes or potentially causing catastrophic wheel failure.