What are the signs of a miscarriage or an ectopic pregnancy? When should I be worried, and when should I go to the emergency room?

I personally experience etopic pregnancy. In the 5th week, my gynae couldn't locate the foetus during the scan. In my 6th week, I had extremely sharp pain in my lowerright abdomen. I thought it was cramps and tried to sleep it off but the pain only grew stronger and stronger. By the time I was operated on, the surgeon said I was lucky because if I had come in any later, I would have bled to death. The egg had ruptured in my fallopian tube, and I was bleeding internally and lost 2.5l of blood.