Not sure whether this is the right place to post this one but here goes...

With DS 1 I got regular AF back straight after post partum bleeding. With DS 2 (3 months old) I got it back straight away too. The doc said to go on the minipill and I did, only to get AF every two weeks. So I went off after about 1.5 months and haven't had anything since. I did a pregnancy test which came back negative but DH said I could have tested too early. I'm starting to freak out that nothing has happened. Is this common for AF to come and go again? I was so regular straight away with DS 1 that I expected the same with DS2. Any advice? Should I test again? No symptoms except nesting like crazy.