no menstrual cramping or bloating when I was bleeding

Hello! I am 21 years old. My boyfriend and I are trying to have a baby . I don't have regular periods, but I have been on a diet and been taking vitamins. I had three regular periods since I have started my diet. So my boyfriend and I have been trying to have a baby since February 18th. I had my period on February 11th to the 16th. Well March 1st I started to bleed a little, and I have never had this to happen. It went on until I woke up on March 2nd. I had no menstrual cramping or bloating when I was bleeding. It is too early to take a pregnancy test and I don't have a Doctor's appointment until the beginning of April. My boyfriend and I are scared that it is something other than pregnancy. We would like some help. Both of us would really appreciate it if someone would tell me something good. Thank you!