I happened to have around 200 lbs of passengers in the rear seats, and another 75 lbs of luggage in the trunk. is this what made the difference? this time I only had 70 lbs of car seats in the rear and nothing in the trunk.
It's hard to say. It's usually impossible to drive twice in the exact same conditions, but once you're driving in a straight line you should be fine. It's when you stop and take off or turn that you will not grip and slide around.
In terms of driving knowledge, there's not much to it. If you press the gas pedal while turning, you will spin out because the rear tires will spin faster than they can grip, but if you press nothing and just steer, your car will turn safely. This works the same in the summer, except the point at which your tires stop gripping is much higher.
The TCS/ESC system also kicks in immediately which helps keep you from spinning out but you just have to not press the gas pedal when you're slipping a lot, that's all you can do.
At the end of the day, if you drive in the snow often, get snow tires. They're more expensive than summer tires, but you can also buy them slightly used because they go down in price by like 80%. I see used tires for $200 a set at every garage and online all the time and you can pay someone $40 to swap them on your original set of wheels.