Personally, I have always struggled to find enjoyment and meaning while working at a big company so I would ask yourself if a big company is right for you. If you decide to stay, try to make a couple of friends. People need to eat so see if anyone wants to eat lunch with you. There are always people who have been there for decades who understand how everything fits together, so seek those people out. Play the "new guy/gal" card, and see if you can get some time with them just to tap into their historical knowledge and start building a relationship with them.