Harry would likely be devastated. He has always been in the spotlight, whether he liked it or not. Now, being ignored, he'd feel like he's in a different world. He might start to isolate himself even more, thinking that he's better off alone. However, he also has a strong sense of justice. So, he'd start to investigate. He'd look for any signs or clues as to why everyone is ignoring him. He might even suspect some dark magic at play. As he digs deeper, he could become more self - reliant and less trusting of those around him until he figures out the truth.
In this kind of fanfiction, perhaps Harry feels extremely lonely. He might start to doubt himself and his worth. Maybe he tries to find ways to get noticed but always fails. For example, he could be left out of group activities at Hogwarts, and his friends seem to not care about his presence anymore. This could lead him to explore new aspects of magic on his own, away from the usual crowd, and in the process, he discovers some hidden powers or secrets that eventually make others realize their mistake of ignoring him.
Harry would probably be very confused at first. He's so used to Snape's animosity towards him that when Snape forgets who he is, it would be a complete shock. He might also be a bit suspicious, thinking it's some sort of trick. But as time goes on, he could start to feel a bit of pity for Snape, especially if Snape seems lost or confused without his memories of Harry.
If his friends continue to ignore him, Harry could become sad and withdrawn himself. He might start to isolate more, spending time alone in places like the Forbidden Forest or an empty classroom. He might also lose his confidence in himself, thinking that he is not worthy of their friendship. In his loneliness, he could focus more on his studies or some solitary magical pursuits, trying to distract himself from the pain of being ignored.
Harry would probably be heartbroken. He trusts Ginny deeply, so her betrayal would be a huge shock. He might initially be in denial, not wanting to believe that Ginny could do such a thing.
Harry would probably be overjoyed at first. After all, he has always longed for his parents. He might start to look for ways to make it happen, like searching for magic spells or ancient artifacts that could bring his parents back.
At the beginning, Harry would be frightened. He's in an unknown place with Loki, who is known for his trickery. But Harry is no pushover. He would quickly gather his courage. He would remember all the times he's faced danger at Hogwarts. He might try to communicate with Loki to understand his motives. If Loki reveals that he wants to use Harry's magic for something, Harry would try to find a way to outsmart Loki. He could pretend to cooperate while actually looking for a weakness in Loki's plan. Harry would also be thinking about his friends at Hogwarts and how he needs to get back to them, which would give him extra motivation to fight back against Loki.
He could be shocked. Maybe there are some fanfictions that take a very dark turn or have unexpected pairings that he never thought of. He'd probably need some time to process such strange ideas. And he might also be curious to see how far the creativity of the fans can go. He might even get some new ideas about his own life from reading some of the more imaginative fanfictions.
At first, Harry would be in disbelief. He would think it was some sort of joke or misunderstanding. But as the reality sets in, he would become a bit of a loner. He'd still have his sense of right and wrong, so he might continue to fight against the dark forces on his own, all the while hoping that his friends would come to their senses and realize they made a huge mistake in betraying him.
At first, Harry might be confused. He would try to figure out what went wrong. He might search his memory for any signs that could have led to this betrayal. Then, he would likely experience a range of emotions from sadness to rage. Depending on the nature of the betrayal, he could either try to win them back by showing them the truth or decide that they are no longer worthy of his friendship and focus on his own path, maybe even leaving the wizarding world for a while to clear his head.
He would probably be very confused and heartbroken at first. He might isolate himself from others as he tries to make sense of what has happened.