That does seem fairly early to diagnose an ectopic pregnancy. I had an ectopic pregnancy back in June of last year. It took several blood tests and ultrasounds to diagnose the ectopic pregnancy.
Either way, you were treated for an ectopic pregnancy and you need to be monitored. Once you are given the methotrexate shot you need to follow up with your dr in timed intervals to monitor the progress of declining hcg levels. If your numbers are not declining enough, another injection may be necessary. If the pregnancy is still viable and is not ectopic, you will need to be on a high dose of folic acid to replenish what the shot took from your body.
Also, once your hcg levels have reached zero, if this is a non-viable pregnancy, you should be on folic acid too. It is possible to concieve again, but I would work closely with a doctor. An ectopic pregnancy can damage or partially block your tubes, making another ectopic pregnancy a chance. Personally, I did the HSG test and it cleared out some debris and allowed me to get pregnant again fairly soon after the ectopic pregnancy.
Good luck in your journey and I hope you got the anwswers you are looking for!
Your doctors were really quick to say it was Ectopic and it might not have been at all. You saying it was unwanted could also have made them rush the decision as well...(it's a horrible thing to think about but doctors do it a lot) A cyst doesn't actually mean there's going to be complications. Often they form in early pregnancy to help supply the progesterone till around 12 weeks when the placenta takes over. Generally until your levels are 2,000 or higher, (sometimes this doesn't hold true for all women) nothing will be seen on an ultrasound. The fact that you had just had a period two weeks prior also makes me think you were far too early in pregnancy for anything to have even shown up. It could take a week to a few weeks for your levels to drop. You will need to go in to make sure they continue to drop over the next few days. I'm sure you'll be able to get pregnant again one day. I would advise you to avoid wherever you went though. They sound....shady. Good luck.