"two days behind" is correct and usable in written English.
You can use it when you want to indicate a certain time frame or gap of time. For example, "We are two days behind schedule."
On the sixth day of walking, they reach the town of Nogotino, two days behind schedule and lashed by a freezing wind.
The halfpipe is expected to be ready for practice on Sunday, at least two days behind schedule.
Too short a beard led to 10 days in jail; long hair, to a haircut or two days behind bars.
"With BP I feel I'm always two days behind in information, and when I ask a question I don't get an answer".
Thousands of enthusiasts began play here today in the American Contract Bridge League's Fall Nationals, two days behind the usual schedule.
Or maybe we are in the park, squatting next to toddlers with the collective glazed looks of a people perpetually two days behind in sleep.
After 12 days, they were four days behind Sea Witch.
A third ship bearing supplies was about five days behind.
After six days' shooting, the production was five days behind schedule.
One year, five months, and four days behind, which places him in late June ,2002.
Andrews spent six days behind bars before he was released on bail pending an appeal.
