Taking a break

I have a mental disorder that has become worse over the last month. It is causing fights between my boyfriend and I like me trying to force him to propose, thoughts of him cheating, even following him to work to see why he isn't talking to me. I know logically heisn't cheating i just can't help feeling this way. I just started anti-depressants last month and my doctor says that my mood change could be caused by this. However my therapist said it would be a good idea to take a break from my relationship until I am stable to lessen stress and prevent damage. What is your opinion? Take a break or not?