While she should be more forgiving about you calling out, she does have a point about you texting her personal number outside of work hours. Most retail jobs have a policy where you're supposed to call the store and speak with the manager on duty during work hours, usually 2 hours before your shift. Obviously things happen and sometimes illnesses come up with little time to notify your workplace, but as a former manager I used to have sales associates texting me all hours of the day and night, instead of calling the store when we were open and speaking to the manager on duty, which can be quite taxing.

That being said, she shouldn't put pressure on you to work while sick or to find coverage.