Am I pregnant?

My husband and I have unprotected sex all the time. In the beginning he would always pull out however this whole month he’s been cumming inside me. Which by the way is fine as we are ready for a child if one comes along.

My worries is last month he came in me a few times during my supposed ovulation time (according to the app) however I started my period 15 days late. This could be due to February being a short month.

Anyways this month I am not to start my period until early April however, my lower back has been hurting me a LOT. And my breasts have been firm for a few days and then they went back to normal. In addition, my left side abdominal looks a little swollen and my left side stomach hurt a little a few days ago. When I shared the pain with my husband he said it could be a fetus. I have never been a parent and my husband has a child from a previous relationship so I expect him to know more than me and take his words as an expert. I’d still like to know what symptoms a pregnant woman may have besides what google provides. (Last month I took the symptoms that google gave me and noticed they all mean I would be pregnant yet I begun my period late).

I would appreciate kind words and helpful responses rather than the mean, smartass ones I’ve gotten in the past. Thank you.