They can do a C-petide or GAD test to help determine your type...
But I am suprised that they haven't told you that your lowering of the insulin could be due to the honeymoon period which is likely at 3 months you are still in..
Normally when a T1 is diagonised they still have some ability to produce some insulin but not enough to support blood glucose control.. And when insulin is injected this actually gives the pancreas a rest, and also it can supress the aummune attack the pancreas is suffering..
So inject insulin is very low level and it's not unheard of for some newly diagnoised diabetics to actually come off insulin for a short period of time before finally having to return to for good when they start to come out of the honeymoon period!
So I suggest keep a very tight eye on your blood glucose levels just incase the above it what is happening to you, a short stint without the need of insulin support