dustincanada- first, a very warm welcome to the forum!!!
Yes, please REMOVE that collar pronto! IMO, NONE of the flea "control" products sold in pet stores are things I would even SHOW to my cats!!! Many are quite dangerous and some have even resulted in cats' deaths. In the USA, the FDA has started an investigation into them.
I'd suggest a quick Vet visit because you're obviously new to the "flea thing"...if she has some, there are SAFE remedies that the Vet can give you - and, s/he can also show you how to find/check for future flea "visits".
Now...about the "tired" symptoms....sometimes, if a cat has a really "bad case" of fleas, the cat can appear to be tired or run down. That's because the flea bites have resulted in the cat losing much blood. I don't know if that's what's causing her to appear tired, but, for me it would be a clear message to take her to the Vet.
the more i learn about (some) people, the more i luv my cats