GMod suddenly not using my GPU

GMod and all other source games have suddenly stopped using my GPU. They ran flawlessly a few days ago and now I can barely get 10 FPS. Drivers have been fully updated for a while and I have not installed a single addon, driver, or update in a couple of weeks. I have set them to run using my GPU (as well as any steam executables) instead of Auto-selecting in Nvidia control panel but this has not changed anything. I have removed my launch options as well. Any suggestions?

I can post my specs but I do not think they are necessary.

EDIT:

After changing some settings for my steam executables, I was able to get every source based game except for GMod to use my GPU. Still unsure of what the problem is.

] mat_info
ShaderAPI: shaderapidx9.dll
Shader API Driver Info:

Driver : nvumdshim.dll Version : 2533352100663611
Driver Description : IntelĀ® HD Graphics 4600
Chipset version 32902 1046 283645026 6

EDIT 2:

It appears that disabling transparency for hl2.exe in Nvidia control panel fixed the problem but disabled high shadows. Adding -force_vendor_id 0x10DE -force_device_id 0x1180 to my launch options added high shadows back. It still shows Intel in mat_info but aside from that, everything seems to be working perfectly fine now.