Hello Kvetiny,
One thing I want to note, is that Antidepressants tablets do play a role to some of us in changing diabetes management and blood sugar levels 100%. Not to all of us, in fact, it will be a small percentage but it does!
The difficult thing is depending on which emotion the tablet is trying to target and stabilize, will determine what effect the tablet will have on you and this will vary from person to person. There is no definitive scientific answer on how or why it does lower or higher our blood sugars. My assumption based on your concern, is that until the tablet stablizes and your body and emotions have accepted it's influence, you will continue to see fluctuations with your blood sugars. Duloxetine will suppress your emotions and form a control over them. Because Type 1 diabetes is also governed by emotions ( Hense when furious we will see a rise! ), until the tablet is settled in the system and dictating your emotions, will you probably see settled blood sugars again. This is of course my experience in psychology and understanding living through it. I hope this may be more than help a GP who doesn't lead our lives.
I was on Sertraline for anxiety ( Big Mistake ) and ended up coming off Insulin altogether last year, a week after I started taking it due to Hypos ( Only positive from taking it ) and a combination of a good honeymoon. When I stopped taking the tablet, I went from 4s,5s and 6s to the 20 readings within 2 days. My theory is that Type 1 diabetes is caused by a major Anger / Sadness event months or years prior to diagnosis, this is why we still don't have a REAL confirmed cause because scientists cannot see emotions when stored into the gut. But that's another discussion!
Hope you get your blood sugars settled soon! Just give the tablet some time to settle around the body.
All The Best
Rhys