Help! Advice needed re.sick leave and new job

[requiresimprovement]

Hi, Many of you were amazingly helpful and supportive a couple of months ago when I was having a very hard time at work due to some dreadful working conditions. As a result I have been signed off work due to anxiety for the last half term. Thank you guys for your support and I wonder if I can ask for more advice?

Before I was signed off I was successful in getting a new job and resigned from the dreadful one I had. Because the interview and resignation came before my illness I obviously had nothing to declare about it in my application. However... should I say something to my new job now? I ask because my new head has asked for a meeting with me at the beginning of next week, with no indication what the meeting is about. It could be nothing but am terrified it is about my absence. Could they take back my job offer because I have been off work sick? Should I have told them even though it happened after I'd accepted the job?

I have been having some talking therapy recently and my therapist is sure that the reason for my illness was simply due to the poor school and environment but I'm worried my new job won't see it this way. Feeling very stressed and anxious again. Thanks for any advice.