Be not afraid; pursue fun
You need to discuss this with your group first.
I'm quite concerned that this may impact our game very negatively. Personally, my character shuns gold and does not possess a value over treasure, but there are several members of our group who are completely driven by it. I'm scared what could possibly be done with this much gold, as I am fairly new to D&D and I don't quite know what is available to those with heavy coin purses.
- It's not all about you, it's about your group experience.
- Your other party members see opportunity where you see worry. Go with their gut.
- You might screw up: so what? Failure and screw ups can lead to hilarious and memorable fun. (We play games to have fun, mostly).
- You are being given a chance to explore a question millions of people have: if I won the lottery, what would I do with all of that money?
You won the lottery, so you now get to role play the answer to that question.
Studies have been done on lottery winners, which found that quite a few have blown their winnings and been back where they were to start with within a year or so of winning. Your objective? Don't be that guy! Make something with this windfall rather than blowing it on (whatever).
Decide as a group
The number of mundane things you can purchase with that much gold is impressive: ships, small castles, iron mines, gold mines, wagons to start a caravan business, horse flesh of the highest quality, raising an army to accomplish (mission X). The list is bounded by your imagination. These are but a few things to start investigating which might also lead to further adventure.
Example:
"Hey, someone hijacked our silk shipment last week. Let's get after them and get it back, and see which crime lord (or commercial rival) is behind it!"
Your DM is inducting you into a time tested mode of play that I am very familiar with, called "Give 'em enough rope!" The operating theory is that, as a DM, you give your players enough rope to play with. They'll either hang themselves or make a hammock with it. Either way it can result in some memorable fun.
Bottom Line: what you do with this is Have Fun with this new pile of loot.