I’m at a loss

Has anybody experienced reoccurring chemical miscarriages? I have literally had every test in the world done including chromosomes, which came back normal all my hormones normal however I cannot keep a pregnancy. Seems like every time after implantation it fails. I’m at a loss I have gave up got pregnant this time know that it’s ending in a chemical Due to high pregnancy test now nothing today. Supposed to start tomorrow. Has anybody experienced this and found the reason exactly why ? I have had like 9 confirmed by doctor anybody take metformin did that  help my doctor prescribed me metformin 500 mg but I’m scared to take it anyways I guess I’m just looking for any insight that one day I will be able to be a mother again