Ovulation

Please give me help and advice!

I took three pregnancy tests Friday and they were all positive. I was not trying to conceive but was also not on birthcontrol and relying on the pull out method. Unfortunately I am in a bit of a pickle depending on the answers to the many questions I have. Firstly, can you ONLY get pregnant when ovulating? I have been tracking my cycle with two different apps but this was only going to be my 3rd/4th period since I got it back after having my daughter. Secondly, if I had sex and conceived on March 30th would I still have had a period April 3rd? I will be going for an ultrasound Saturday when I should be around 5 weeks and 3 days based off of my last period. So I guess I shouldn’t stress my self trying to figured out when I conceived since they should be able to tell me.