Feel so frustrated and upset

Megan
I have no clue what's going on! I didn't have my period at all in july and I thought I was pregnant but every test I took was negative and my blood test was negative. Then my period came at the regular time in august...well now it's September and my period is late again and all my tests are negative :( I don't know what's wrong with me this had never happened to me. Has this happened to anyone else?