I am angry and wonder why this trial has befallen me. Is this anger a sin?

Asking 'why me' is natural for a hurting person, and feeling it is not a sin as long as it does not lead to blaming or resenting Allah. Even the prophets were tested severely and complained to Allah without losing their faith. Channel that anger to the right place: into prayer and sujud, not into actions that hurt yourself or others. Allah says: “Seek help through patience and prayer” (Surah al-Baqarah 2:153). Remember that a trial is not a sign that Allah hates you; sometimes it is a way of raising your rank and wiping away sins. Give your heart time, and if the anger drags on and weighs on you, talk to a counsellor or a knowledgeable person. Slowly, the question 'why' turns into 'what next'. See counselling.