"I want to go to Europe"
You can't do that next week. Well, you can, but you won't be able to use your phone there without paying ridiculous roaming and data charges.
If you unlock your phone and hop a plane today, you can stop at any mobile phone shop at your destination airport, give them five euro, and they'll give you a new pre-paid SIM card with five euro worth of credit on it.
That's enough to use your phone as much as you like for the duration of your two-week vacation. Top up with another fiver if you want a couple GB of data while you're at it. And you're done. Just remember to pop your old sim back in when you get home.
Travelling the rest of the world is all about picking up cheap local SIM cards in every country you visit and enjoying cheap calls like a local. You're about to lose that.