Cycle length

Vanessa

If you are normally regular, let's say you have a 27-28 day cycle and then you suddenly have a 35 day cycle, does that mean you are supposed to assume your cycle length has changed or it could just be an exception? It happened to me last month and now I do not know what to expect. I'm supposed be in my tww but these two weeks might be actually much much longer if my period length has actually changed.

Please give me your input.

Thank you.