After having my baby girl 9 monhs ago my periods have been up and down I came off the depo as me and my partner want more children, for the past 3 months I have only been having 2-3 day periods and they mostly come early when I have had a drink of alcohol. It happened this month 3 weeks early after having a drink now I missed it on the du date I took a test but came out negative can anyone help and explain why this is happening.