Gear up for O the don't O at all?

Brandi-lea • Khaleesi-May Dizney Van Vliet - my precious daughter born on 23.6.15 👶🏼🌸
Hello ladies, I usually ovulate cd16 or cd17 and have been charting my temperature everyday for at least a few cycles. 
​I take it at the same time every morning and always nudge it under my tongue in the same place everyday.
This cycle my chart has been slightly odd and I noticed that about cd4, yesterday I had a temp rise and although it supposed to stay elevated for 3 days, usually I know I've ovulated as soon as I get that temp spike after cd16 or cd17.. Well, yesterday I assumed i was 1dpo but this morning my temp dropped again, so have I not ovulated yet? Thank you in advance :)