cannot be diagnosed on the same day, unless basal body temperatures are being keenly followed; even then, it takes at least a couple of days. She may have conceived earlier in all possibility as a HPT gives a positive test during 4-5 weeks of pregnancy and not earlier. You should immediately contact a specialist and take proper treatment. Self-medication
without proper diagnosis of pregnancy is dangerous as it can cause heavy bleeding and infection. Hope your query is clarified. Take care.