Being on top will not prevent a pregnancy.
Can I ask how you know you were not ovulating? The phone apps are not a good thing to use for ovulation. The only way to know for sure when you do ovulate is to buy a kit and test for several months. Many women think they ovulate in the middle of their cycles but this is not always true. It can happen at any time during your cycle.
Yes, you could be pregnant because you used no protection. Condoms are cheap and can be bought any where. A woman's clinic will give them to you for free and you can also get other forms of birth control for free depending on your income.
You had sex 2 weeks ago so you can buy and early pregnancy test. Use it with your first morning urine.
Do you know when you're sue to start your period? You could wait until then and of you don't start then you can buy any pregnancy test, a cheaper one, and it should be accurate by the time your period is due.