Constant pain for months, have no idea what to do now.

In the last 3 months, I've (F25) made 3 ER trips as well as around 4 GP visits for the same symptoms, with no diagnoses or medical care, and at this point I simply can't afford to keep going back without hope for help. I guess I'd just like some opinions/advice as to what I should say at a next appointment in order to get somewhere, or what I could do to help myself. Here are my symptoms on a timeline:

• 3 months ago, presented to ER with a sudden sore lower back and lower abdomen, as well as dizziness and a feeling of fluid retention (tightness) in my legs. Dismissed from ER after a clear urine test.

• Week after, presented to ER again with the same heightened symptoms. Was prescribed Cephalexin on the hunch that I had a kidney infection.

• Taking Cephalexin temporarily alleviated symptoms, but made the veins on my temples throb heavily for the course's duration.

• Week of, I present to the ER again. Doctor registers my blood pressure as lower when standing, and higher when sitting. Books me in for an ultrasound.

• Week after, symptoms return. I attend the ultrasound as well as have a blood test done. Everything comes back clear.

• Up to now, I have been suffering the same symptoms. In the last week, my lower back and pelvic region has been unbelievably painful, and my heart rate feels very high and intense.

Notes: My last 3 periods have been between 5-7 days late, and for the last year, I have been struggling to stay asleep during the night, as well as pass stool (the longest I had waited to pass stool was 8 days - last year).

Sorry it's a lot to read. If anyone has any advice or anything I would really appreciate it, as I'm feeling a bit scared and a bit lost at the moment. Thank you :)