I hadn't been able to sleep since our last meeting.

He hadn't slept at all since the night before last.

You haven't slept at all since the attack and not much before then.

I have often been unable to go to sleep since this happened.

You can sleep with me tonight, since your bed's all smoked.

From his appearance, he also hadn't slept since the previous morning.

He had not slept since the previous night and then poorly.

He had not really slept since California; his body and mind could barely function.

She hadn't been sleeping too well since the disappearance, but last night she'd barely got under at all.

Jack had been unable to sleep well since the first such visit, knowing that it could happen again at any time.