help! +OPK, no temp pattern

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I came off the pill in June and have had pretty irregular cycles since then (101, 51 and 41 days respectively). I started temping for the first time this cycle (here's a picture of my chart) but there's no detectable patten. I'm on CD29 and am supposed to have my big O today. I got a positive OPK yesterday. How long should I continue with the OPKs? How will I know I ovulated if there is no temperature rise on my BBT chart?