is it normal?

hi guys! I just stopped my depo shot last May 3,2014.. and I had my period on May but month if June my period was very light and only took 3days.

Now my partner and I trying to have a baby..that's why i stopped my depo On May 3,2014..

And now this July I still don't have my period,.my partner and I always had sex.1st week of July we tried pregnancy test but it went Negative.. and I still don't have my period..I tried it again 2nd week of July but still.negative...and now I still don't have my period...but don't feel any signs of pregnancy... iam a mother of a 4year old girl.

how long will i gonna feel some pregnancy sign? and it'll be almost a month I don't have my period..what is that??

pleeeeaaasssse anyone... thank you all.