You titled your question “sexual abuse” so I’m guessing that the “this” in your question is about being abused. If so, please understand that it is not at all unusual for a kid who is being abused to feel bad about herself — even if she knows it is not her fault. It’s not at all unusual for a victim to distance from the feelings that go with what is happening. Often abused people report feeling numb or like what is happening isn’t really happening to them. Your mind is actually taking care of you by separating you from what is happening. This is one of the hallmarks of Post Traumatic Stress Disorder.
You probably can’t deal with this yourself. First, the abuse has to stop. If you can’t stop it yourself (and you probably can’t), then you need to call on someone who can take care of you. Confide in an adult you trust. The next step is to get into therapy. A therapist will help you reclaim your ability to feel your feelings and will help you make sure the experience of being abused doesn’t interfere with your ability to make loving, intimate relationships. Please find a therapist who can give you the support you need and deserve.
I wish you well.