Definately. I "think" I had a miscarriage at one point in time. I did some research and found that like 4 out of 10 women miscarry their 1st pregnancy. Most don't even know about it and then they have normal healthy pregnancies after that. I did! I had my daughter a year ago and everything went perfect!
Yes you can. If you miscarry that early it could have been a chemical pregnancy.
I think it is possible. I had a miscarriage at either 3-4 weeks (that's what the MD estimated it to be). I'm not really sure why, though. Sometimes you have one and don't even know it. In my case I had severe cramps and heavy bleeding, then 2 days later I passed the fetal tissue. I hadn't had a period for 2 months though and had repeated negative pregnancy tests. The miscarraige happened on December 25, 2007 and my last negative pregnancy test was December 2, 2007. That is why we think I wasn't that far along. Hope this helps.