Need some serious help!

Ok guys please help me out here!

I came off the pill 24th of March on the 26th of March I got my period for 9 days (normally only goes for 4 days). I am now on cycle day 38 and have not had a period again, me and my husband are trying for a baby but every test I take is a BFN so I definitely don’t think I’m pregnant.... I’ve been super tired very day and have had light cramping for the last week, but nothing like my pms cramping, also have been experiencing headaches quite a lot the last few days.

I came off the pill last year for a few months and my period was still perfectly on time and I never had a cycle this long.

Is this normal?

Has anyone else experienced anything like this before?

I’m so worried that I’m not pregnant and it’s something really serious.

Any advice would be appreciated :)