the same amount of people use the internet in my home
that has a negligible effect on your latency.
Right, it's back to 130-140. Idk what's changing.
It's not on your end, it's likely on your internet provider's end. They're not using the optimal route for your internet.
Imagine this: you need to fly from london to the US east coast. The easiest way is to fly across the atlantic ocean. What your Internet provider does however, is they send your flight to asia, then to africa, then to australia, then to the US west coast before finally bringing you to the east coast. The time it took to get there is longer. that's basically what I think is happening to your internet connection (the example was a lot more extreme though)
This happened to me before, and when I called my provider they told me one of the main internet cables under the ocean was being maintained and was not operating, meaning they had to make a detour, increasing my ping. After a while it got fixed and my ping went back to normal.