The United States is so large, and the areas are so different, that many Americans move several times before they find a place they are happy in. So a lot of Americans are in that situation just within their own country.

However, you need to be sure that you have given it enough time, and that the things that are making you unhappy aren't things that are generally the same across the US.

If you want to move at the end of three months, my advice would be to stick it out. I think you should give any place at least a full year. Of course, if you move to someplace where the weather is unbearable, say North Dakota, then I'd say go ahead and bolt.