I got my second contraceptive shot, it's not depo it's called mesigyna. today i got my period and it's very light dark brown. is it normal?

Yes normal: Yes this is normal. Like all combination hormonal contraceptives (progesterone + estrogen), there will be changes to your menses. They have higher progesterone effect than estrogen. Not only do they prevent you from ovulating but they also prevent your uterine lining from building. This will make your periods lighter especially over time. Your cramping should also be less.