Is omeprazole safe?

I was taking omeprazole for heartburn/acid reflux prior to getting pregnant. It was as needed which ended up being 1 or 2 pills a week. Is it safe to take during pregnancy? My family medicine doctor said to stop and take tums (those don’t work for me). All internet searches say it is safe for pregnancy but the doctor scared me.

I don’t have an appointment with the OB until the 29th. It’ll be my first ultrasound. I am currently 5 weeks 2 days.

I’m just curious because I don’t want to harm baby but the heartburn is awful.