welcome to healthcaremagic Forum.
When did you have your periods last time? By the history given it really seems that detecting pregnancy
on 17th is too early. At least you should be 4-5 days overdue and the first morning urine sample is used for pregnancy test. You just wait and repeat pregnancy test. Also, the size of uterus
varies with your hormonal
levels even during the cycle. So, there is nothing to worry.
Dr. Rakhi tayal