mine went haywire after bub 3 and 4. after number 4 I got it 7 days on 7 days off.. Drove me mental.. I had an US as I had a fibroid during my pg but they couldn't find a reason for my almost constant bleeding and then it settled down into a normal cycle ..

I would probably see a Dr to rule anythying out.. More then likely they will just tell you it is your body getting back into a normal rythm