How do I get the diagnosis for my puffy lymph nodes?

My lymph nodes has exploded 3 times in 6 weeks…I puff out and feel like a marshmellow. I have a new PCP, going to fibromyalgist Thursday. I know this is a sign of serious infection, and/or cancers
and need to know what is going on with me. Where should I go?
I’m due for mammogram and when i get up nerve for colonoscopy, that is also needed. I woke up during scope and have issues with that one.