My period is 9days late I have taken 4 pregnancy test and everyone of them came back negative,am I testing to early or is there something really wrong

I don’t feel any cramps or anything.I get lower back pain but every now an then but I feel that’s because I am BBW. I miscarried my first child back in February 2020 I been trying every since. My time of trying 13+ yrs🙍🏾‍♀️🙍🏾‍♀️🙍🏾‍♀️🙍🏾‍♀️ I just want to be mom,doctors can’t tell what’s the problem or they just don’t want to say