Body playing tricks on me????

Amanda
Hi everyone.. This is my first post... 😀
My husband and I have just started "officially" TTC for a couple months. I am usually regular.. About 26 day cycle.. We really tried to get pregnant during the time this app told us to.. 
Now I am a week late. Which never happens.. I don't feel horrible but don't feel great. Nipples are tender. Slight cramps and I don't feel like I can get enough sleep..  I seem to be having some kind of slippery discharge and it makes me think my period is starting.. But then nothing. 
I took a pregnancy test yesterday morning and it was negative. Is it common to not get a positive pregnancy test a week after your period was supposed to start.
Also read that it could be a hormonal imbalance.. Which is quite possible because I have put on some weight, like most newly weds tend to do.. Haha 
Can I be psyching myself into this?? Can my brain be causing these symptoms because it has a sense of humor???? Ugh.. Either get a positive result or start your period already, amanda!!!