Advice please!!!

Sorry if this is TMI. I am 22 years old and been married for going on 4 years. My husband and I have been TTC for over a year for #2. Last month I had my AF for 3 days it was brown color and then turned normal color and went away. I was supposed to start again on 17 and still nothing. pregnancy test came back neg. I can't really explain it but my body just feels off. I'm scared it's just all in my head bc I'm trying to hard. Please any advice!!!!!!