"Symptoms" question!

Tatyana
So I am 2 weeks "late"(i have irregular periods) I have taken numerous tests all are negative. But I have been having some weird "symptoms" like my back is killing me, bloated, crampy, moody amd now (TMI sorry) I have the runs. I have 2 other children (unexpected pregnancies) amd have never had any of this before. Whats going on? HELP!