welcome new friends, welcome.
take a deep breath and relax. another goodie to add to the many oddities we experience. our bodies are sending the wrong messages all the time. this is wrong, that is wrong. come on body, panic. now i went thru all the tests and at the end i was told, surprise, here is another "thing" to learn to live around. and learn i did. i am very careful rising and sitting. blood flow is altered when we stand or sit or lie. since we are so sensitive to any change, and it is magnified one hundred fold, we are hit hard by it.
it is always a good idea to talk to your doctor, have whatever tests they deem necessary, or the ones you want, and be sure it is only another facet of fibromyalgia.
this all takes time to adapt to. you hang out with us. some of us are veterans at this game. myself for sure. you will find kind and compassionate people here, and a wealth of knowledge. ask any question you want. no doubt someone here will have a shared experience, and you both can relate.