breakthrough bleeding on the pill

So i start a new row of pills every Thursday. Last Thursday was the start of my second row, and I usually take my pills at 6pm everyday. This time I forgot and took it at 3am (which was Friday) and took my Friday pill at 6 as usual. I'm on low dose orsythia btw. I have never had bleeding like this on the pill and I have been on it since last September. Is this something that's normal? I've been lightly bleeding since last Saturday.