Hey guys, I just had my very first camping experience, and some strange sounds at night bothered (somehow scared) me, so I'm posting in the hope that someone can tell me what it might be.

It was at a campsite in Bruce Peninsula national park (Ontario Canada), not sure if geographic location really matters but whatever.

The sound woke me up twice at night (def. after 12am but not exactly sure what time).

It sounded like someone (or something) stomping hard on the ground while passing by near my car in which I was sleeping, I could even feel the car shaken slightly on each step.

I thought it might be some large animals (maybe a bear from my newbie mind), and then I did some Google research today, realizing bears don't make that heave sound when walking.

So... what could it be if it wasn't something from my nightmare?

P.S. I'm already scared so please, don't say Bigfoot.

Moose? Horse or cow if farmland is nearby?

Could even be a deer stomping, which they often do if curious or alarmed.

Carnivores (like bear or cougar) walk very softly, so most likely it was a herbivore.

Strange noises in an unfamiliar place often sound much louder than they really are, at least to me!

I generally wake up for a lot of noises my first night out (actually, I often enjoy listening to them!) but I sleep through them after that.

Moose was also my first thought.

Another possibility: were you camping with friends who knew this was your first time camping? It’s not unknown for new campers to be “initiated” their first night out. (It might be helpful to know that the bag limit on snipe is 5, at least in Ohio. Your chances of limiting out are very slim.)

My most memorable such incident involved some brand new Scouts. The trop went to summer camp, and they were assigned a campsite near the edge of the property, on the other side of the fence from a pasture full of cows. About an hour after they were all snug in their tents, I saw some of our older Scouts headed into the woods, circling around the camp to the fence. All of a sudden they came running through the camp, mooing at the top of their lungs and ringing a big cowbell. Never will forget the chaos that followed...

Something with hooves. We spent a few hours in the Backcountry of Yosemite one night listening to a few deer thumping around our tent. Very noisy.

No matter how many years you camp or backpack unusual sounds at night can make you take notice. It's very normal and simply part of our survival instinct, which is a good thing. It's important that you understand that the odds of that noise turning out to be a hostile animal are very rare. I've backpacked and camped for several decades and the most common culprit for those noises usually turns out to be deer.
If you still have a difficult time sleeping without knowing the source of those noises I would suggest getting a canister of bear spray and keeping it next to when you sleep. It's not a bad thing to also have in your pack when you go hiking. I've had many encounters with bears over the years and also cougars (one as close as 125 feet) but have never found a need to use my spray but you may find it gives you some comfort.
As noted above, stay calm and enjoy the wonderful sounds you find while camping.

Through the years I have observed that mice grow to at least 50 pounds and have feet the size of dinner plates when they stomp around your tent at night. Every sound is amplified when you are in a tent in the wilderness at night. After a while you just adjust and ignore the sounds. Seriously, mice, squirrels, and deer are the most likely night visitors.

Ha! I remember one night about 12 miles in. I'm sleeping soundly and my wife wakes me up:

"Wake up. I think I hear a bear over there..."

I listen for a minute and reassure her. She promptly goes back to sleep.

I spend the rest of the night listening for bears over by our bear can...

My wife and I were camping as newlyweds, when she nudged me awake and frantically whispered "Do you hear that!"

"Yes" I said, barely awake at this point.

"See what it is!" I blearily unzipped the tent and stumbled out, then stood and peered over the tent in the direction of the noise.

"Can you see it?" she said.

"Yes."

"What is it?"

"A skunk."

"Get back in the tent!"

On a couple occasions, these guys have kept me awake too:

They're not big animals, but they're kind of oblivious and make a lot of noise.

EDIT: OP, I'm pretty sure that's not what's keeping you awake in ON, though, as they don't venture further north than the US .

Which is why it's a good idea not to venture out at night without a headlamp or a flashlight! Skunks do not get off the path to the restroom to let you get by!

Speaking of stomping deer, one time a curious deer actually started pawing at the back of my tent! Fortunately the tent survived, and when I yelled I heard the deer bound away!