Applying for citizenship

[Sos79]

Hi,
I was married to a British citizen and now I am divorced. I came to the country in 2003 and then I moved abroad in 2010, and I used to come back to the uk every 2 years so I dont lose my ILT visa, then I returned to the uk in 2015 but during this year I stayed out of the country for few months then in 2016 I started working again in the UK and I applied for my BRP and have been paying tax since then.

My question is, do I have to stay for 5 years to apply for my british citizenship and passport and if so, can I start counting my return to the uk from 2015 putting in mind that I didnt work during this year and I also travelled a lot and stayed 3 months outside the country and another time for 2 months? Or shall I start counting my 5 years from 2016?