Thanks for the query.
Sometimes urine pregnancy
test kits can give false positive results.
But as all the 4 tests showed positive results we cannot rule out the possibility of pregnancy.
The first change of pregnancy is endometrial thickening.
So you wait for one more week. If you get your periods by that time it is ok. If not you go for blood test
for pregnancy which will rule out the possibility. If the test comes positive go for ultrasound