Many questions

I am a 42 yr old female, About 6 years ago my doctor sent me for an MRI on my lymph nodes in my neck because she had noticed they had been swollen for a long period of time. MRI showed several enlarged lymph nodes and nodules on my thyroid. Was told they were gonna keep an eye on them and do imaging yearly. I have went every year and they have stayed the same and some have slightly increased, both nodules and lymph nodes. Not really giving me much to be concerned about.

Recently, I have been fighting pneumonia,  been on steroids and antibiotics for about 6 weeks, with no help from them. Having a difficult time breathing,  very sore throat and a little cough but no usual cold symptoms like runny nose or anything.  Went to the ER where they did a CT scan and found a 12mm x 15mm groundglass mass and several nodules with the biggest being 5mm on my lungs. Ct also indicated that I had enlarged mediastinal lymph nodes. Told me to wait 3 months, if its goes away it's nothing, if it's still there after 3 months that it could be an aggresive process that needs to be treated. 

 Also, would like to add that blood work that came back abnormal:

MPV High 11.8

Creatine Serum Low 0.4

Low potassium 3.2

AST High 87

ALT High 76

And RBC in urine

I am going to my Dr. on Monday to speak with her about the results of the CT. Should I be okay with waiting 3 months or should I demand a PET scan and/or biopsy? Is the size of the mass something i should worry about? Just looking for opinions because I have had the enlarged lymph nodes for years. Maybe the two aren't even related, or, could they be?

Thanks so much for any advice