1) I haven't slept since the moment I heard the news.
2) I haven't eaten anything SINCE nine o'clock this morning.
3) I've had a bad cold SINCE last weekend.
Тут не во времени дело, а в употреблении FOR (в течение) и SINCE (с какого-либо момента).
Плюс исправила небольшие грамматические ошибки