has anyone used these i took my girl to the vet yesterday , she seemed out of sorts she was mated 28 days ago , both really good ties , the vet scanned her and used a draminski as well but with no results, i could have swore she is pregnant , bigger nipples, swollen bits, more loving, the normal things they do, the most important thing is my girls ok , vet couldn't find anything wrong with her, i know scans can sometimes miss so early on but wondered if the detector was more acurate thanks,