I'm 26 years old. And I've already have DM2

I have normal weight and I exercised a lot. I don't have any symptoms, just high GB levels.
I'm depressed, and I got the diagnosis earlier this month.
I'm taking metformina already. First week 500mg, since then 850mg. Is it normal having dizziness and nausea after taking the pills? I don't want to change the treatment and have to use insulin this soon.