Set somewhere between seasons 1 and 2. Sorry if it's a little off, I haven't watched since the end of season 1 (Supergirl is my TV superheroes limit haha) but sometimes I just need to write a little May and Skye.
It's the little things you notice when someone starts to pull away. Yes, sometimes they have the best of intentions, but when May started to pull away from Skye she couldn't help but feel there was negative emotions behind the distance growing greater by the day between them. Skye had given up trying to fix things for the time being. Maybe May felt Skye was beneath her now that she was in charge of more things within SHIELD. Whatever the reason, May was keeping her cards close to her chest and Skye knew there was no point in forcing anything out of her. She had tried before and it just made the situation worse. Besides, Skye wasn't exactly the most open agent on the Bus.
Skye knew May was busy, she wasn't expecting things to be the way they had been before it all changed. Before Hydra ruined everything. But she wasn't expecting the cold, calculated moves from May. Skye felt like May must think she was stupid, that she simply wouldn't notice all the little things she had done to distance herself further and further from Skye. Skye couldn't deny she was cut deep by it all. She hadn't had the most stable of backgrounds as a child and hadn't really had anyone to talk to. Then she became a SHIELD agent and met May and Coulson. She finally felt like there was someone who cared enough to push past the standoffishness and see the broken person underneath. The person who just needed someone they could rely on. But now Coulson was too busy running the whole organisation and trying to weed out any Hydra agents and May was avoiding her like the plague. Skye sat alone in her tiny room aboard the Bus and allowed one small tear to escape before angrily brushing it away. This was her own fault, she thought. This was the price she paid for being stupid enough to let someone in.