Is it serious if there is something in the uterine cavity?

Patient's question:

Recently, I've been experiencing some abdominal pain and lower back soreness. Last night, I had a fever and was worried it might be pelvic inflammatory disease, so I went to the hospital for an examination and had an ultrasound. The doctor said there's something in my uterine cavity and suggested a D&C (dilation and curettage) to wait and see. After that, they prescribed Gatifloxacin tablets. Today, I started my period. Could you please tell me if I can take this medication now that my period has started? Also, could you please tell me if having something in my uterine cavity is serious? Can medication treat it? Will it affect my ability to get pregnant? I hope the doctor can give me detailed answers to each question! Thank you! It's urgent. First follow-up question: So, should I stop taking the medication for now and go to the hospital for a follow-up after my period ends? Second question

Doctor's answer:

Hello: Your symptoms may be caused by the onset of your menstrual period, as the endometrium thickens during this time. The doctor recommended a D&C procedure, but now that your period has arrived, I believe there is no problem. If the symptoms persist after your period, you can seek treatment. It will not affect your ability to get pregnant.