Chronic Pelvic pain and lower back pain

Patient: I am 28yrs old, female. I have a pelvic pain since March 2014. the pain is constant and severe, the pain covers all my lower back, ovaries area, vagina and clitoris. I feel bloated all the time and the pain gets worse after any sexual activity or even wearing jeans. I have no change sin my period ” very regular”, no vaginal discharge, no bleeding, however, I feel my colon is not well. I have alternating diarrhea and constipation, anus pain after bowl movement, and anus pain when sitting down too. I have seen 3 doctors and had two abdominal scans and pelvic endoscopys in two different clinics both show negative results, blood tests were negative, smear test negative, STD test negative, UTI test negative. my GP doesn’t know what causes the pain and I am very worried as it affects all aspect of my life. I can’t exercises, I can’t wear any pants or jeans, I can’t have an intimate activities, and always feel weak and depressed. Please can you suggest what should I do?

Symptoms: Chronic pelvic pain, lower back pain, ovarian pain, vaginal pain, clitoris pain, anus pain with bowel movement and sitting down, pain after masturbation or sex, fatigue, high blood pressure.