Low lympocytes - should I worry

Hi everyone, I have had my GP on the phone today (do they ever have a day off??) and she has seen my bloods results from the 26th and my lymphocytes are now low at 0.57, I don't know if this is a little low or a lot.... They were considered normal on my results from the 20th so this has happened is a short time span. I have been re-started on Azathioprine and went up to 50mg on the 25th, I really don't think it would be able to affect things that quickly though? I am to call my IBD nurse first thing in the morning to confirm that I can continue with the Aza. THIS is where I am now a bit panicky, I developed neutropenia last time on this drug and now this today is making me think I will have to stop it again I really don't want to have to do this as this is my only chance of avoiding Humira. Am I perhaps getting wound up over nothing? Any info/advice would be appreciated.