Hi I had a miscarriage back in June, and since then my periods have been 40 days apart. My last period was on Feb. 19 and my next one should have started on March 31 but instead there was just a little blood when I wiped for 2 days and that is it. I took a pregnancy test but it was negative. Did I take it too early? WHat else could it be?

First periods will change, your new cycle may be 40 days, nothing wrong with that.

But you have to be 14 days late before you can test

You could have just had a very light period, not unusual at all.
You could be pregnant, and tested too early.
I don't see how either one is 'wrong.'
Even worry can delay or lighten a period, or even skip a month.