Mirena/Depo

So last year after my second child I got on depo. Then my ob recommended Mirena due to weight gain. So the second month of me on depo I got the iud inserted. Kept it for 6 months and got it out the end of May. I immediately got a cycle May 23. Now nothing my cycle is going on 44 days now. I keep cramping but no spotting or bleeding. I feel little flutters everyday. Took pregnancy test 2 weeks ago and negative. So im figuring my body is just out of whack trying to get back right. Anyone ever went thru this?!!!!