cramps but no bleeding! Is is possible i may have conceived?

Hi. I am 28 and my husband & i are trying to conceive our second child. We have been having regular intercourse (every other day!) My last period started on Feb 12th 2008 & i am due my period tues 18th March. On fri 29 Feb i had some light bleeding & some mild cramps that only lasted the day. Since Tues this week i have been having some mild cramping again but no bleeding (just lots of clear discharge). I am also a bit constipated, have tender breasts & am a bit concerned that i am cramping with no bleeding. Could it be possible that we have conceived this month? I had none of these cramping symptoms in my first pregnancy.

Thanks for taking the time to read this.