I will insha’Allah try to answer your question as best as I can, but remember I am relatively new to Islam and if you are still curious after reading my answer, you want to speak to an Imam or someone who is more knowledgeable.
The first thing to note is that you can’t see every aspect of someone’s life. They may “seem to get everything they want” and perhaps they do, but is this really the case? Who knows what family problems they are having behind closed doors? Who knows if they are suffering from ill health or are really happy? Driving a nice car does not necessarily mean that they are as happy as they look. The problem with comparing our life to someone else’s is that we only see their highlights, whereas we experience all of our highs and lows.
Just because they seem to have nice possessions and an easy life while you struggle, does not mean that this good fortune is a gift from Allah. All is Allah’s plan and who can say why he does what he does? Part of the beauty of Islam is the knowledge that though we may struggle now, our future is always brighter.
Who knows where these Christians will be in five years, and where you could be in five years.
Also, try to think about the areas in which you are lucky. Firstly you have been blessed with Islam. And while you may struggle to meet ends meet financially, I am sure you have wonderful parts of your life: a loving family, kind friends, etc etc.
The final point to consider is this: the unbeliever’s afterlife will be one of Hell, whereas your’s will insha’Allah be one of Paradise. Allah tests us in this life so that we may prove ourselves and earn a place in Jannah. You may not be happy right now in this life, but just imagine the endless happiness that awaits you in Jannah.
I will be praying that you find peace and happiness in this life, and hope my followers will do so to!