Missed 2 periods, had 2 periods

[Sunshineclouds11]

Hi,

my cycle has always been spot on 28/30 days, I've never missed or went longer.

I had a period, waited to come the next month - nothing.
had a period the next month, then again the month after, nothing.

100% not pregnant. When is the time to investigate? Does it need investigated?

im 36

I don't think the gp will do anything at all until you have missed three in a row. Also, at your age it's not uncommon to skip periods either.