12 days past period. Had a miscarriage 6 weeks ago

I’m 12 days late on my period and today (April 18th 2019) I got some brown and clear discharge. I’ve been having small cramps in my lower abdomen and other symptoms. I did have a miscarriage at 8 weeks that ended on March 4th 2019. I took a pregnancy test on March 27th March 29th and April 3rd and they all came out positive but could this be a chemical pregnancy? Or could I really be pregnant again !! How long after a miscarriage can you get pregnant?? Me and my partner have been trying since March 11th 2019 which was a week after my miscarriage. Help !!!!