10 days late!

I am 10 days late and my cycle is typically 27 days. I last took a test a few days ago, but it was negative. I am assuming I ovulated late. But when should I start testing again? Or do I just assume no period this cycle? That is extremely rare, as I am very regular and have only ever had two skipped periods ever. (I am 25) Anyone had a positive test after being so late?