Oh dear. Had your team not thought of the repercussions on your blood sugars.
Would it be possible to get them to do what we call a sliding scale of insulin ?
So that the amount of insulin you give depends on your blood sugars. Use your normal long acting, but if your sugars are high give a rapid acting like Novorapid to quickly reduce the BSL. For example, if BSL 6 - 10 use 4 units Novorapid, if 10 - 16 give 6 units, if > 16 give 8 units. I'm sorry but we use different blood sugar measurements here. Normal is 4 - 6 for us. We would get you to check your sugars 4 times a day. Before and after meals and last thing at night.
Whoever manages your diabetes must be able to come up with a plan Paul.
Hope you get some help with this.
Be careful and take care,
Tammy

Caregiver/advocate to Husband Kris age 59@ diagnosis
DX Dec '10 SCC BOT T4aN2bM0 HPV+ve.Cisplatin x3 35 IMRT.
PET 6/11 clear.
R) level 2-4 neck dissection 8/1/11 to remove residual node - necrotic with NED
Feb '12 Ca back.. 3/8/12 total glossectomy/laryngectomy/bilat neck dissection/partial pharyngectomy etc. clear margins. All nodes negative for disease. PEG in.
March 2017 - 5 years disease free. Woohoo!