Hi, paranoid ex-Windows user here again!

I was on Youtube last night watching a multi part video. When I went to watch the next part I did so by trying to right click and open it in a new tab in Firefox. Now I don't remember hitting anything to save a page, but somehow an HTM or HTML file was saved to my download folder before my eyes. I didn't double click on it and instead just deleted it. I believe the HTM or HTML file was called "Watch" or "Watch This".

I can't remember if these were in the folder or not while the HTM or HTML file was, but later on I noticed that there were 2 other files in the download folder. I forget the exact names but I remember they were a string of letters and or numbers. And I also believe the file made mention of "part HTM" or part HTML".

Now my concern isn't a virus because as I found out through here there are no Mac viruses. But what happened just seems a bit strange. Part of me is afraid someone else could have put those on my computer (not physically, I live alone now). How likely is it I would have saved the page accidentally, and what about those 2 other files I found in the folder after deleting the file? Any thoughts on this besides me being extremely paranoid?