The title "The World is too Much with Us" sounds funny – we usually say "The world is too much for me." Funny-sounding things can often be interpreted in several ways, and this one is no exception. First and foremost, it describes the condition of industrialized society. The experience of the modern city, with all its people and shops, is overpowering; for it to be "too much with" means something like "it's so much I can't handle it." Just think of it as analogous to how you feel when you see a really bright flash and have to close your eyes, or when you scowl because you just bit into something that's way too sour.
Two other possible interpretations depend on "world" referring not to industrialized society but to the natural world itself. From this perspective, the title could mean something like "human beings are a burden on the earth," a parasite that upsets a natural balance. Alternatively, it could mean that the natural world is "too much" for us because we have a lot of other things to worry about, as in "I have things to buy and worrying about nature is just too much for me to deal with right now." All of these different meanings of the title are activated in the poem, which is obsessed with the different ways in which people are too busy for nature and no longer have the time or the ability to experience it.