She was in love with Terashima Yuhi for so long that other guys did not register in her head. It's not like she was oblivious to their feelings, but it did not matter to her. The love she has for Yuhi was unexpected, which was why she never thought of confessing to him. But nowhere she is with that very person who she thought was out of her reach before.
After eating breakfast, the two of them rolled back onto the bed. Sumire wanted to do something more productive, but Yuhi was still sleepy. So he pulled her onto the bed, wrapped his arms around her, and fell back asleep.
At first, she tried to go back to sleep too. But she realized it was futile. Whenever she is with Yuhi, those negative feelings vanish. No, it stops temporarily. But it does not disappear. She wonders why this person cares for her so much. Say something happened in the past; that was the past and not the future. Why does Yuhi feel so obliged to her now? It's not like she saved his life or anything.