Thought it was ectopic

So I went to the doctor today with intense cramps and pains in my stomach. They took a pregnancy test and it came back negative so they sent me home. They called 5 minutes later saying that the negative turned into a slight positive and sent me to the hospital to test for ectopic pregnancy. They took blood and said I'm far too early to tell. And my hormone isn't high enough. But she did an exam and said everything felt normal. They are going to keep a very close eye on it since I'm having such bad cramps. No bleeding though. Has this ever happened to anyone?