Router blinking fast and slow internet on most sites.

Certain sites are super slow to load both in my pc and phone. Other sites and apps seems to work fine like tiktok, YouTube, ig, and other commonly used sites or apps but the ones that I only use for specific tasks either won't load or very slow. The ethernet cable on the back of my pc is also blinking fast orange light which I assume is bad, and the Lan on my router is also blinking fast. Can anyone help me?