After 15 months pregnant

Hi everyone.

We have a daughter born in 2014.
After trying for months, we went to the GP last month.
They referred us to the hospital.
I had several internal ultrasounds there to monitor my cycle.

Last week I took a pregnancy test... and I'm simply pregnant.
I just can't believe it.
In the end, I got 4 positive tests.

But now I feel incredibly unsure.
In 2 weeks, we can go to the gynecologist for an ultrasound.

Are there more who got pregnant spontaneously after a first round at the hospital?