Well, I don't know if this will help you but I would like to share an anecdote with you. My daughter found her Dell laptop with SSD unmanageably slow. It turns out everytime she was shutting off her laptop, she was just pressing the power button and not performing an actual shutdown.

So then when she pressed the power button again, her desktop would restore, and she'd launch another chrome browser or another instance of Word, etc, etc, and the laptop would get slower, and slower and slower over many days.

Make sure you are performing a shutdown using the Windows Start icon on the left-most end of the taskbar. If you leave your laptop on for days on end, perform a restart using the Windows Start icon.

Do those two things, and report back what you are experiencing. We might be able to help more knowing how you use your laptop.

Also, there may be some power settings you can use to speed your laptop up, for example while on battery.

Good luck.

From what you describe, it almost sounds as though your SSD is not working properly.  Did you replace a HDD a while back and get normal operation out of the computer for a while with the SSD? 

Forgive me if you already know or have done this, but you might run "CHKDSK" just to see if you have any issues with the drive.  If you have Windows 10 loaded on your computer, press the "Windows" button and type "Run" in the box, then enter chkdsk and hit "Enter".  I believe the steps for Windows 7 are to go to the command prompt and then enter "chkdsk" on the command line.

I hope this helps.  Let us know what you find out.

Steve