A source tells ET that, while the 37-year-old singer is currently vacationing in Miami "trying to relax and have fun" with her boyfriend, Sam Asghari, "sadly changing locations doesn’t make things any easier."
"Her fans can see in her video that she is concerned about what everyone thinks at all times and it’s stressful for her," the source says of a video Spears posted on Monday, where she claimed that paparazzi doctored photos of her to make her look "40 pounds bigger."
"Britney has always been concerned about her body because her physique is so much a part of her career," the source says. "She feels she needs to look great at all times. Right now she just needs to focus on stability and getting the help she needs without feeling she is under a microscope."
"She’s fragile and her emotions are up and down," the source adds. "The family and her doctors are just glad her behavior has improved a bit but they know this is an ongoing problem that could get worse at any moment and they are helping her to regulate and remain on her medication."
Spears' situation, the source says, "has been very up and down" and "she's been struggling tremendously with insomnia."
"Her team is trying to get her to establish a daily routine, but the problem is she doesn’t have structure in her day or a schedule," the source says. "They are encouraging her to develop a routine in terms of her bedtimes and wake-up times."
A source previously told ET that, when it comes to Instagram, Spears' situation "hasn't changed."
"When she wants to post a video, she posts a video, despite advice from family and friends," the source said. "Of course, sometimes her people are concerned about how she comes across in her videos, but right now Britney would like to exercise her right to do whatever she pleases."