Advice / experiences - strange cycle

[Badleg]

I have been having fertility issues totally unexplained as both me and husband have had all tests and all is fine. We have our booking in appointment at the fertility clinic on Wednesday.

So I usually have a 28 day cycle very regular. I have had a lot of scans and ovulate late post day 14 usually around day 15/16

My past 2 cycles lengths have been odd with a 24 day and a 27 day.

I am late this month currently on day 30. However took a test yesterday am which was negative.

I had a small amount of bleeding this morning so thought period was here and used a tampax which when I went to change was clean. So the bleeding hasn't actually fully flowing which I usually get.

I am a bit crampy and just feel a bit nauseous which could be nerves!

I think I should just test again. But just wondered if anyone else had been through similar experience?

After 5 years of trying I am so scared to test again.