Hello,
Welcome to the ehealthforum and I am really glad to help you out. From the description of your symptoms, you seem to be suffering from intermenstrual bleeding. It could be due to several causes. First, you should get a urine for pregnancy test done to rule out a miscarriage as the cause of bleeding if you had unprotected sexual intercourse prior to that.
Other causes which need to be looked into are fluctuations in hormone levels, hypothyroidism and fibroids in the uterus. It could also be due to a genital infection, cervical polyps or ectopic pregnancy.
You should consult a gynecologist for the diagnosis and treatment as without examination, confirmation of diagnosis is difficult. I sincerely hope that helps. Take care.