I need relationship advice quick going mad plz help?

am a guy of 23 i need help quick i feel like ending my life my gf cheated on me i found out cant believe it am so hurt ive kwn her for 5 years been together for 10 months n this is killing me i dnt knw what to do am sooo mega hurt and having a nervous break down already went into shock 3 times plz someone out there hlp me b4 i do something b4 its to late this is nt a joke am in series need of advice i feel sooo low some one anyone plz help me