brown spotting

we have been ttc for nearly 3 years oct 2016 i miscarried before i found out i was pregnant then again end of feb 2018 and then finally had a positive test in may after being 2 month late sadly 2 days later i lost that that one to im now 20 days late brown spotting feel ill little cramping but every test comes back negative but my daughter who is now 13 when i was pregnant with her test said negative for over 2 months but was alot younger then after i had her i was told i only had a 5% chance of having anymore but 2 years ago i went a had test done again and them odds have come up now so im not sure if i can carry anybody else ever had the same problem