Confused about my due date! 😤😤

My last period was feb 18th 2019 and i was supposed to get it again around the 18-21 of march well it never came! I didint feel much except shortness of breath and fatigue and i was tired most days but i also have a toddler running around. I took a preg test at the doctors on march 25 and it was negative well my period still never showed up and i was superrrrr emotional i mean crying so much all day long. Well i took another one on march 30 and i got a positive!! So does that mean i ovulated late or what? Should i count from the ovulation day or lmp? 🤨🤨🤨🤨🤨