You shouldn't credit the asset account with all of the proceeds. You should only credit it with the amount of your cost basis at the time of the sale so that the account ends up with a zero balance. Any remianing amount is your gain. Your entry should be a split entry with the other amount as the gain on sale of the house. You might want to create an income category for this or else you can use the "_RlzdGain" built in hidden cateogry.
I assume you took the "net cash to you" number and put it in your checking Account and the other side of the entry went to your "old house" Account? That's not exactly correct because that net cash to you probably does include some element of other costs (e.g., allocation of property tax) that really should go somewhere else, but it's probably "close enough" for your purposes.
You have two ways of going now:
Either way will work from the standpoint of getting a properly stated Net Worth, but the second entry is "more correct" from an accounting standpoint.