What would be the symptoms of a meth overdose?

My sister just started using meth after 1 year. I know she shouldn’t blah blah blah so I don’t want to hear all that.
Anyways her and her bf did it last week with 2 other people and she only did a little bit but yesturday she got a 60 and shared 40 with her bf and his friend and today she’s doing a 20 with her bf after not sleeping or eating for 2 days
She’s not doing it all at once she’s doing 1 hit every couple of hours.

Well im worried that since she hasn’t smoked it for a year and this is only her 2nd time doing it. could be to much for her? Could she overdose? What are the symptoms of an overdose and when to go to the hospital?

Please help give me answers

But if you’re going to be talking shit then don’t bother I told u the story to get a more of a trustworthy answer and that’s it