I'm glad you're here for another edition of Q&A with Dr. Q.! And I'm glad to hear the question "why is by pet rabbit shedding so much?" For some rabbit owners, all this extra fur can seem like a lot, and it could make you concerned about your bunny's health.
Our technical term for shedding is "molting". Rabbits will usually have four molting periods per year: two smaller molts, and two large molts. They do this to help regulate their body temperature as the environment and climate change with the seasons. The larger molting periods are, of course, in the summer and winter. During the summer months, rabbits will shed much of their fur to stay cool, and when winter rolls around, they need to grow out their longer winter coat, shedding that summer/fall coat. Each molting period will usually last between two and six weeks. This is all very general, and the climate in your geographical location will play a large part in the time frames for molting. If you live in Southern or Central Ontario with colder weather and longer winters, your pet bunny's molting periods will be much different than a bunny owner living in the Southern U.S., where it's pretty hot year round.
This is all to say that your pet rabbit will shed a lot as a natural biological occurrence. However, there is a risk of excessive shedding being caused by fleas or parasites. You should have a flea comb on hand to check your bunny for any little infestations. And if something seems unnatural about their shedding patterns, be sure to consult your veterinarian. Other than that, just make sure you have a high quality vacuum cleaner!