I'm 6weeks pregnant and just started bleeding and having cramps is this a miscarriage?

Maybe: Time will tell. We hope for the best outcome, but any woman may have a miscarriage as a normal part of life. If a woman has recurrent miscarriages, there are some known causes (other than really bad luck) such as genetic disorders (like a chromosomal abnormality), autoimmune causes (like anti-phospholipid syndrome), anatomic causes (such as a malformed uterus), etc...