First of her, have your daughter see her pediatrician who will privately address the medical issues of her sexual activity. Then for the relationship between you and your daughter, you may want to see a family therapist or a psychologist who would be a neutral source to help build back the trust issues between you and your daughter. The family therapist or psychologist could also meet with you separately to teach you some coping and intervention strategies in dealing with a teen age daughter as a single parent. The time is now to act before your daughter continues her unapproved actions. Until then, you may want to take away things like her phone, computer, time with friends, etc. However, this may upset her greatly and cause her to rebel even more. I would seek professional assistance as soon as possible. If you have health insurance, call the customer service representatives and they can steer you in the right direction.
I hope that this has helped. Please ACCEPT. Have a great day!!!!