Variance Question NLTRN

[monkeytales]

I just starting implementing HU poker into my daily routine. I play about 5 a day, I know, not a huge sample, but give some ideas on what variance runs like in the HU world. This month, before today, I was 28-12 in HU SNGS with an ROI of 38%. Today was horrible, 5-6. Including a loss in a HU match that was 5x my normal buy in. I figured HU matches would have pretty low variance, looking back, I played badly in one match, and fine in the other 10...help with the variance question please.