Most women who have a miscarriage are more likely to have a healthy second pregnancy. Just relax and take it easy stress isn't good for you right now. Congratulations on your up coming baby!
First off, sorry for your loss, but Once You miscarry Your levels usually return to normal pretty quickly. A lot of women get pregnant soon after because your body is a lot more fertile. Honestly if you missed your period & had 4 positives then your more than likely to be pregnant. Going by your last period if you think your about 6 weeks you need to get into the doctors ASAP. Good luck