I finally got HTTPS running on my website, thanks to Let's Encrypt. I've wanted to use their service months ago or whenever it was first opened up for use, but I couldn't get it running on my old VPS, because of many reasons probably.
Well anyway now I got it running very fast and simple without any issue.
Or well, I had to move out all my VirtualHosts that I had in a single configuration file (000-default.conf) and make them have individual configurations files in Apache's sites-available folder, but after that it went without a hitch.
Enjoy? I guess?