I had similar symptoms starting in April 2017. It took three lymph node biopsies (2 excisional and 1 core needle) and 10 months before I was diagnosed with a T-cell lymphoma called Angioimmunoblastic T Cell Lymphoma (AITL). My local oncologist at the time was absolutely convinced it was not cancer because my lymph nodes waxed and waned. Mayo Clinic in Rochester diagnosed me and we tell people they saved my life. I was in very bad shape by that point. I would recommend CT scans and to trust your gut and keep digging if needed. Here’s a link to a good article on AITL http://www.cancertherapyadvisor.com/hematology/angioimmunoblastic-t-cell-lymphoma/article/597504/
Good luck to you!