Hcg injection today- tested ovulation tonight

So I went to my doctor today and had an ultrasound done on my ovaries. She stated that I had one follicle measuring at 18 mm. She decided to give me an hCG injection and told me to continue to monitor for ovulation and to BD the next 4 days to be sure we have a chance if I do ovulate I’m in the next 24-48 hours...

Tonight after work I decided to take this test and I got this as a result. I have never gotten one this dark with any other cycle.

Is this just because of the injection or could I really be already ovulating between 11 am and now?