Welcome to the club!

I think we've all done something similar to what you did and that's why most of us are here. I know I have. You just need to make a different plan for your next trip. Call this one a learning experience and move on to the fun part.

Coming here was really good idea because you'll find all kinds of great advice on lightning your load. To sum up the best advice look into the "Ten Essentials", the things everyone needs to bring, and then look at what you brought and set aside everything you didn't use if it's not one of the essential items. Then look at what you used and see if you can use something lighter. Don't duplicate stuff. You don't need a big Bowie Knife, and a butter knife, and a pen knife, and a Leatherman multitool in your pack. You'll find one lightweight knife will do. Try to look for things that can be used for a dual purpose.

Once you've read up and finished lightening your load make a plan that's going to be easy on you. Plan a trip where you can hike just a mile, or less, and set up camp. There's no rule that says you have to hike for miles and miles. You have the rules where you're going to be hiking, but a lot of places let you camp most anywhere you want with just a few restrictions, like being 1-200 feet from water, or trails, or protected areas, et.

Take it slow. You don't need to beat yourself up racing along the trail. So what if it takes you 3-4 hours to do that mile. If you're going out to enjoy yourself that doesn't matter a bit. If you find a great spot to sit and enjoy along the way to where you want to camp, do it. That's a really good reason to stop and a great thing to do.

From camp you can do day hikes and just carry the stuff you want for that. Or you can just laze around camp and relax and chill and enjoy being outdoors. So what if you're only 1/2 mile from the trail head. You don't need to impress anyone with how far or how fast or how high or steep you went. None of that has anything to do with the simple pleasure of getting outside and enjoying a few nights in the forest.

And hey, some people find out they just don't like backpacking. That's okay too. You might still like car camping and you can get to some awesome scenic spots from car campgrounds, and sleep outside under the stars that way too, and use pretty much all the same gear.

Aside from that, even without really pushing yourself, the more you hike the easier it will be for you. So don't give up. Just plan your trips different.