OP wrote:
"2.6ghz, 8gb ram , 1tb sata hdd"
The answer is easy:
The internal 5400rpm platter-based hard drive is what's making the computer slow.
If you don't want to spring for a new Mini, you have TWO options to make the old one faster:
1. Open it up and replace the HDD with an SSD
2. Buy an EXTERNAL USB3 SSD, plug it in, and then set it up to become the boot drive.
I recommend option 2. You'll get about 85% of the speed you would see (if the SSD were installed internally), and having the external SSD makes it easy to just "unplug it and take it with you" when it's time for something new.
I'd suggest something like a Sandisk Extreme drive. 500gb would be fine, even 250 will do the job and do it right.
Just take it out of the box, connect it, and use Disk Utility to erase it to Mac OS extended with journaling enabled.
Then, you can either put a "clean OS install" on it, and migrate stuff over.
Or... you could use CarbonCopyCloner (which is FREE to download and use for 30 days) to do a "selective clone" (if the SSD is smaller than 1tb, you'll have to leave some stuff behind on the HDD, such as your movies, music, and pictures libraries, but that won't be a problem).
Switch to an SSD, and you'll come back here and tell us "I never would have believed that such a simple change could make such a BIG difference..."