Possible miscarriage question

Female, 27, 122 lbs, 25 mg of zoloft daily; I am 6 weeks 5 days along.

I started bleeding red yesterday, switched to brown today. Went in for an ultrasound and they found the sac at a healthy size, but no embryo. I had an internal exam where they found that I was not dilated, and the blood looked old. I have another appointment next Friday. The doctor told me it’s just a waiting game now. My questions: 1) Does this seem like a miscarriage? They run in my family (my sister had one last year and both grandmothers had multiple). Aren’t embryos normally visible at 6 weeks?

2) The doctor told me no heavy lifting but did not specify. I have a 25 lb toddler. Should I avoid picking him up?

3) Is there anything I can do to increase my chances of saving this baby?

4) After the internal exam, I am back to bleeding bright red. Is that normal, or should I call the OB again?