I took a pregnancy test every day for 3 days. each line was extremely dark. Risk of tubal pregnancy?

It really doesn't sound like you are having a tubal. I did go through one and lost my tube. My pregnancy test were so faint you could barely see them. The fact that yours are dark are a great sign. Your dr can check your hormone levels (and I believe they always do this) and will see them increasing appropriately. In my experience I had non stop extreme pain in one very specific area (my tube that was rupturing). If you experience severe pain go to your dr. immediately. Some slight cramping is normal in early pregnancy, I had that when I had a successful pregnancy. Please don't worry so much and try to enjoy the fact that you are pregnant! Good luck, have a happy and healthy 9 months.