Could Missed Periods With Back Pain Be Due To Pregnancy?

Could I be pregnant? I usually get my period on the 11th, January came and I got it Feduary came and I was late and didn't get a period at all so march came and I got it on the 16th, april is here and I'm bleeding brown blood. In feb I noticed I felt different and my back was hurting. What could this be we aimed for a baby in january cod I be pregnant