Am i pregnant......help!!!

Well me an my partner have been trying to concieve. I recently have tooken pregnancy test thru out the month they were all negative even went to hospital and they said it was negative...weird thing happened though I usually have very heavy periods and this time I spotted and it only lasted 24 hours could I have recently in a last few day conceieved??? How can I tell? And when should I test again? I need answers I'm so confused :/