Have you got a European Health Insurance Card? (Make sure you apply for one before you leave Italy if you don't). This should cover you for NHS treatment including GPs, but I strongly suggest you contact your university to double check this.
UK diabetics can also get free prescriptions (ask for a form from your UK GP). I am not 100% sure whether these are covered by your EHIC card: if not you'll have a small fee to pay every time you get a script filled at the chemist.
Good luck.
ps And welcome to the forums