Help? Need some info 38 weeks

Im a FTM and I’m 38 weeks and 2 days Pregnant and I just finished having hard sex, Doggy style.. and after I went to use the bathroom and get in the shower but before I got in the shower I wiped and saw a Light color red or pinkish. I need some help I don’t know if it’s serious or I’m just over worrying my self and ready to have my baby lol but my back is aching and been aching all day and is this suppose to happen at 38 weeks ..