Ifelt mouring sickness on a Monday and a Tuesday on that Tuesday I caught my period but it wasn't red it was dark brown what dose that mean and I've been feeling cramps and back pain and I've been peeing more often and constipated I took 2 pregnacie test and it came out negative can you give me and answer to why I feel like this

Hun, you feel like this because you have your period. Many periods start and end dark brown and are red in the middle.