DEPO SHOT!

Has anyone gotten the depo shot before? I got it one time in February 25th 2017. It did a lot of bad things to my body. But I haven't gotten it since then. Has anyone gotten pregnant after one depo shot quickly? I had a period for 23 days. It says I'm suppose to start tomorrow. Well I've been spotting bright red here and there. And also I have a brown discharge a week after my last period and it was a week and a half before I was suppose to start my period again. Any help? I have light cramping especially in my lower back. I've been more horny lately. My weight is fluctuating.