How early can you feel an ectopic pregnancy?

I'm currently 3 weeks 6 days pregnant. I found at 9/10 dpo 3 days ago. Ever since I've been having a dull ache sometimes sharp pain where my left ovary/tube is. I'm terrified it's an ectopic pregnancy but wouldn't it be to early to feel if it was? My pregnancy tests are extremely dark but the pain is pretty persistent although it doesnt hurt excruciatingly. Could it just be a corpus luteum cyst? I'm so worried. My first appt isn't for a while and I dont want to go to the ER unnecessarily. This is my 4th pregnancy and I've never felt anything like it. Opinions?

Below is today's test.