what could this be?

[dee_1660]

Around five months ago, I developed pain in my joints. However, a couple of months ago, this turned into debilitating bone pain. The bone pain is in my arms and legs, but I would say that it’s worse in my arms and I’ve noticed it gets worse at night. Along with this, I’ve been experiencing some other symptoms.
I’ve been constantly fatigued and out of energy and weak no matter how much I sleep, but lately I haven’t been sleeping well because of the pain. I’m also having intense night sweats and I’ll wake up in the morning and my shirt is wet to the touch. Under my jaw, my lymph nodes are slightly swollen. I’m extremely tachycardic; just going up a flight of stairs makes my heart rate jump to around 180 beats per minute-- the worst has been about 200. I’ll also get random palpitations even when I’m doing nothing where my heart is pounding out of my chest between 130 and 180 beats per minute and I’ll feel very out of breath. Over the last few days, my chest has been very tight and a bit painful and I’m having some trouble breathing. I’ve been nauseated and not really hungry lately. I’ve also found a bunch of coin-sized bruises on my legs with no reason for them to be there. I also had dark red blotches on my shoulder that didn’t lose color when I pressed them, but they went away after a few days. However, I’ve been getting rashes all over my body nearly every day and even when I don’t have them I’m really itchy. I also have really heavy periods (an overnight pad will last me a few hours at best) even though I’m on the birth control pill to help with it. I’ve also had some mild stomach aches, recurring constipation, and some occasional sharp pain under my left and right ribs, and bad nausea. I’ve had blood tests for autoimmune disease and arthritis, but nothing has come back positive. The only remarkable things from my tests are an anemia diagnosis, barely low vitamin D (I’ve started supplements since then), and a slightly low white blood cell count. I also have low blood pressure.
I’ve seen so many doctors and none of them can find out what’s wrong with me. I’m getting worse and worse every day and I’m just trying to find out what I have. My daily activities are getting difficult. My friends are telling me that I look exhausted. Just getting through the day is a big challenge for me now. Do you have any idea what could be wrong with me?