An infection of some kind could be one problem. Some of what you described could be one. At this point your best bet would be to see a doctor and request they do a beta hCG count. If this shows you're not pregnant, they can do other tests to see if you have any problems.
Could be encountering some other problems? Like what?
I agree the pull our method is not so effective as some us may want to think. Your symptoms does not really say that you are pregnant. You could be encountering some other problems. Have you missed your period?
If you think that you are pregnant then you should take a pregnancy test. After that is done, if it is negative then you should visit your doctor.
Sometime for reasons unknown test may show negative. Your doctor can have a blood test taken to ensure whether you are pregnant.
i wouldnt know anything about pregnancies but i must tell you that the 'pull out' method isnt the greatest idea because men pre-ejaculate which does contain less sperm but still has a risk of pregnancy. i couldnt tell you more on the topic so i recommend searching pre-ejaculation.