What Are The Symptoms Of Glandular Fever?

My daughter is nine, she has the second dose of tonsillitis in the last month and now has peeling lips, mouth ulcers, glands so swollen that I wonder if it could be glandular fever? She is totally exhausted constantly. I have RA and I am worried about any auto immune links for her. She is on a ten day course of antibiotics. Should I put her through a blood test to check her ferritin and for glandular fever? Thanks