Puppy blues or definitely rehome

hello everyone! I got an 8 week old lab mix puppy about a week and a half ago. I absolutely adore her and I’m growing attached to her which is why it’s hard for me to think I may have to take her back to the shelter. the thing is, I’m a student and I also have to work. so during the day I’m gone for maybe 4-5 hours and when I have to work I’m gone for 9 hours. I’ve had people to check on her but I know this always won’t be the case. it makes me feel like a bad owner when I have to leave her in her pen for a while. to top it off I’ve been having mental health struggles due to academic stress, I just sort of feel bad that she has someone who’s not mentally well. I still take her on walks, feed her, play with her, try my best to train her, and my goodness I can’t stop finding things that I want to buy for her. but a part of me feels guilt for when I have off days. I can’t tell if I have puppy blues or if it would be better for me to return her to the shelter. it’s really heartbreaking for me to do so as again I’ve grown really attached to her but perchance there’s someone out there who’d take better care of her.