Up until about 12 months bubs will go through different stages of waking, then sleeping through, etc. Last week my bub started waking through the night again, but this week everything is all back to normal.
It's completely normal, every baby does it and you may not have changed a thing. It could also be a growth spurt, they have one at 4 months and another at 6 months.
Hope he goes back to his normal routine soon for you.