It sounds like fleas and a flea collar doesn't really do much.
I use feline Advantage on all my cats (frontline stopped working for all my and my friend's animals, but we live in an area where it's warm a large portion of the year and fleas are rampant).
You can also give appropriate dose of Capstar before Advantage to kill the adult fleas within 24 hrs.
I dunno about in Canada, but in the U.S. you can order both of these meds without a prescription.
Either way your kitty needs to see a vet for a checkup and to make sure that's the only problem
More tired than normal can either be anemia (loss of blood from the fleas) or something else entirely, so a vet check is definately needed.