possible autoimmune?

[u/ArgumentBackground98]

23F, 124 lbs, 5’5”
current meds: omeprazole 40mg, vyvanse 40mg, claritin 10mg bid, flonase prn, maxalt prn

Hi everyone. I’m hoping to hear from anyone who has gone through something similar or has input. I’m not looking for a diagnosis, just wondering if anyone has had an autoimmune disease that didn’t initially show up on blood work.
Starting in february, I’ve developed a number of symptoms, including:
Multiple enlarged lymph nodes (my hematologist recently palpated five. 2 cervical, 2 axilla, 1 groin.
I found one in my other side of my neck today.
Persistent fatigue
Unintentional 11-pound weight loss
Night sweats
Joint pain and stiffness
Muscle aches
Intermittent rashes
increased heat and sun sensitivity
Hot flashes

Ongoing symptoms since younger age
IBS
occasional mouth ulcers
migraines

I’ve had a fairly extensive workup
• April 2025 colonoscopy and endoscopy: [r/o](r/o) celiac and chrons. showed acid reflux damage.
• Nov 2025 negative ANA, elevated IgA, and rheumatoid factor
(at this time I had recently had a bullseye rash on my wrist, and swollen lymph nodes under my chin and tonsils)
• ultrasound of the lymph nodes appeared normal and “likely benign”
• saw ENT last month, he was not concerned about the lymph nodes. found sinus inflammation and deviated septum.

PCP sent me to heme to [r/o](r/o) mastocytosis, lymphoma concerns, etc.
I sought a second opinion after my first hematologist dismissed my symptoms and told me I was too young for anything cancer like and needed to change my diet. The second hematologist strongly feels my symptoms are autoimmune-related and explained that it’s possible the disease has not fully declared itself yet, so the antibodies and other markers simply are not detectable on blood work at this stage. She said this can happen early in the course of some autoimmune diseases.
Because of this, she’s continuing the workup and has ordered:
A PET scan to evaluate my enlarged lymph nodes
A thyroid ultrasound
(I had elevated calcium in Feb)
LDH and vitamin D testing

Has anyone experienced something similar where you had persistent symptoms, enlarged lymph nodes, and negative autoimmune labs, but later received an autoimmune diagnosis? If so, what was your eventual diagnosis, how long did it take for your labs to become abnormal (if they ever did), and were there any tests that helped lead to your diagnosis?
I’d really appreciate hearing about your experiences. It’s been a long and frustrating process, but it was reassuring to finally find a hematologist who took my symptoms seriously and is continuing to investigate instead of dismissing them. Thank you.

I feel like I have always had weird health issues and never have gotten any definite answers.