Transmigrating to the Sui Dynasty as the Empress

After catching her boyfriend cheating, she argues with him, and his mistress shoves her into the road. A car coming straight toward her hits her. When she wakes up, she discovers that she's transmigrated, and to the Northern and Southern Dynasties, a period history books barely cover. At least she's a young lady with a comfortable life. But what's this about getting married soon?! Wait, the man she's marrying is Yang Jian? Isn't he the future Emperor Wen of Sui? Does that mean I'm...