TTC post miscarriage

So I was 5/6 weeks preg and started bleeding the week of August 8th. Doctor was out of town the next week; so didn't get in until 8/25 HGC test was 173 Retest Monday 8/29 87. Confirmed miscarriage. Went back to Doctor two weeks later (Monday) and HCG was 11. I've had this weird feeling of early pregnancy this week...lots of bowel movements. Frequent stops to the bathroom, lots of tiredness and sleepless nights. I retook a cheap preg test today. Neg after a few mins. But just went back and see a faint line. Is this just evap? If I had 11 HCG on monday; could that have been the start of a new preg? I think the min to get a positive on a preg test is 20...thoughts? Anyone else not have a period post miscarriage and get preg again?