I just found out I am 5 weeks... I have been having symptoms for 3-4. Period symptoms are similar to pregnancy symptoms so I just figured it was coming.
Some peoples bodies are more sensative, and sometimes if you know what your 'looking for' its easier to spot. But also sometimes if your trying or worried about it then you can just make syptoms up in your head. The only way to really know is with a test so give it a while and take one.