Icons not showing issue with WordPress

I having some serious trouble with WordPress for the past few days and I haven o idea what to do about it. Here’s what happened:

I was looking for ways to improve my PageSpeed Insights score and found a really good post that was sort of a step by step guide of things you could do. I really did help a lot, the problem is I messed up with more than I should’ve. I installed a bunch of different plugins and added a bunch of different code that would do certain things to help make the website faster. While my score improved, a lot, something things were broken. One of them I haven’t been able to solve.

So icons on my website, and even the dashboard, aren’t loading. All I get is an empty square. If you go to geek.com.do you will see how a lot of the icons for social media and other stuff just aren’t loading. Here’s what I have done so far to try to fix it, without a result:

-Deactivated and uninstalled ALL plugins. Didn’t fix it.
-Reinstalled my theme from scratch. Didn’t fix it.
-Copied new WordPress files (all of them except wp-config.php and the wp-contents folder). Didn’t fix it.

I have no idea what else to do. Any ideas?