I just finished first year of med school about a month ago and have two dogs. I am married, but my wife was even busier than me concerning time this year so it's not like she could take care of the dogs all of the time.
I feel like, with our dogs' personalities, having two of them is necessary. They are best friends and definitely keep each other company when my wife and I are not around. Also, my school does have online lectures and our dogs are inside of the house the majority of the time when my wife or I are home (we have a small back yard). They get to go out several times a week whether its walks or to the dog parks, but there have been weeks where we only got to take them out on the weekends.
However, you have to know your dog(s) and the personalities. Some dogs may not be ok with being without another dog, while some may prefer it. I can't tell you what do do, but I can tell you from your end that it will not likely ruin your life. My life was fine and I have to cook meals for one of my dogs every day because of her allergies.
Best of luck.