It sounds like your manager is non-verbally messaging you to look for another job. In his defence, that is somewhat better than laying you off or putting you on a PIP, so as others have said, it's probably a good idea to look for another job.
In any case, for your personal growth, it is helpful to understand why things have gone wrong between you and the manager (or the whole team).
One of your theories seems to be that the manager brought in a friend to boot you out. That would explain his behavior, but not that everyone else on the team is giving you the cold shoulder.
I am purely guessing at this point, and I don't want to offend you - but it is possible that you have upset the whole team. Either slowly through your behavior, or there was a meeting, or something else. This may have been fully unintentional by you, and you do not seem to be aware of it. For your next job, it'd be helpful for you to understand what has gone wrong!
Your text reads like you're not a native speaker? I'm not either ;) If you move between cultures, there may be things that are acceptable in your own culture, but not in the culture you moved to. E.g. the way to disagree or discuss things. Maybe that's the area where this misunderstanding has come from?
You could try to approach a team mate, or the manager, and ask openly about the situation. Tell them you sense something is wrong, you don't understand what you have done wrong, but you'd like to fix it.
In any case, for your personal growth, it is helpful to understand why things have gone wrong between you and the manager (or the whole team).
One of your theories seems to be that the manager brought in a friend to boot you out. That would explain his behavior, but not that everyone else on the team is giving you the cold shoulder.
I am purely guessing at this point, and I don't want to offend you - but it is possible that you have upset the whole team. Either slowly through your behavior, or there was a meeting, or something else. This may have been fully unintentional by you, and you do not seem to be aware of it. For your next job, it'd be helpful for you to understand what has gone wrong!
Your text reads like you're not a native speaker? I'm not either ;) If you move between cultures, there may be things that are acceptable in your own culture, but not in the culture you moved to. E.g. the way to disagree or discuss things. Maybe that's the area where this misunderstanding has come from?
You could try to approach a team mate, or the manager, and ask openly about the situation. Tell them you sense something is wrong, you don't understand what you have done wrong, but you'd like to fix it.