If you can replace the physics class until you’re on firmer ground with the math, that might be a good idea. I’m assuming you’ve already set up regular appointments with the math tutoring center and the advising center/student success office, but if not, make that a priority.
And ultimately, your mom is going to be your biggest cheerleader, so do the hard work of being honest. Sure, she’ll probably be upset at first, but mothers want their kids to succeed, and she might even be helpful for keeping yourself on track in the spring.