I would definitely say take a test!
Your lining can be thick if you are pregnant and/or getting close to your period
I want to test but scared I'm getting my hopes up for no reason. Looking at all my dates and the scan it should be here already esp after what the scan nusre said that my lining was def thick as if I was about to start. Deep down I think I've got the dates wrong but never have before. I am going to give it till Friday and see what happens.
If your period was due last Friday, definitely test.
I'm also having this happen atm, but I know I ovulated late, last week my lining was at an 11 and I was 6 dpo so I'm expecting my period this week, unless you know that ou ovulated late, you always have a chance of being pregnant so I would take a test and see how you go :)