Buying and selling houses

Yes, the gain you had from the sale of the home is taxable.  Given that the gain is taxable income, the next question is how should that gain be characterized.  In other words, was the sale of the home part of a business, or was the home a primary residence.  If you are in a business, the purpose of which is to buy and sell houses for a profit, then the facts about the sale of this home (i.e. original cost, repairs and upgrades, sales proceeds) would be entered on a Schedule C, Profit or Loss From Business.  This type of gain would be characterized as ordinary income.

However, if you are not operating a business, then the gain from the sale of this home would be characterized as a capital gain, and you would pay tax on that gain.  Because it appears that the home was owned for less than one year, the gain would be considered as a short-term capital gain.  If you had owned the home for more than one year, the gain would be characterized as a long-term capital gain.  Long-term capital gain rates are lower than short-term rates, and thus are more favorable for taxpayers.

While it does not appear that any of this gain would qualify for the capital gain exclusion, if you are interested in learning about when such gains do qualify for capital gain exclusion, here is a link to an IRS webpage which discusses the capital gain exclusion.  

IRS: Sale of a Home