Pregnancy Concerns: Late Period & Negative Tests - Medical Advice

Question
i am 14years old.first day of my last manstural period was february 7 and it ended on 12th of feb.most importantly that period was late as first day of my second last period was 29th of december.on4th of feb i had intercourse with my bf.on19th of feb i did urnine pregnancy test which was negative.on 25th FEBRUARY i did B-HCG,Quant(titer) blood test which showed value of < 1 mIU/ml.now i wanna ask can i still get pregnant and did i test in time that is exactly 21days after intercourse.can that 1mIU/ml result in pregnancy.thanx in advance for ur insight into my problem

Answer
First of all, pregnancy test (even blood test) do not show accurate results until a month or more after conception so there is no way to tell that soon after.  It is possible you are still pregnant but you need to wait a couple more weeks to take another pregnancy test.