Looking for some reassurance or advice 

I am 26 years old. A month or so ago I noticed a pea sized lump just above my collarbone on the left side, it was moveable and tender and I didn't think much of it. Since then I developed a rash that the doctor described as "purpuric?" On my legs , and my skin on legs became quite itchy but bareable. I'd also wake up with random bruising and began just feeling hot constantly but wouldn't have a fever and lost 6-7lbs in 3-4 weeks but my diet had been the same. I would even get breathless and my arms would ache just getting my kids ready .  I saw my doctor who felt my neck and then went and got another doctor to come in and they said they could feel more lumps on the right side of my neck and they could be reactive but were now referring me for bloods, chest X-ray and then referring me to ENT who would most likely do an ultrasound. Around  two days after this appointment the rash has started to spread and the lower part of my stomach has swollen but isn't painful at all. 

I get the bloods done first if this is all clear will that mean everything is ok and I won't need the other scans?

or is there any advice you can give to help me understand everything.