Welcome Salb.
How to cope with instability in diabetes? Well, as you're only a few months since diagnosis, you're probably still in the honeymoon phase, which means your pancreas is still occasionally and irregularly producing insulin, which does change things without giving warning. That phase will pass eventually.
Best tips I can give, are "don't be too hard on yourself" and "life is more than diabetes". Any questions, please ask - several of us were diagnosed type 1 as adults, so will be able to help - or at least, recount our experiences.