The price is dropping down recently, But Bitcoin is always profitable, because it have the most promising potential among crypto currencies, and the number of its traders around the world is really huge. So The price is going to increase again after some time, and that's the best time to buy more BTC as the price is low.
Yeah the price is dropping in the start of the year but only about 20 % from the highest peak then stablize it is the indication that it started to launch back at any point.and according to some economic expert Bitcoin will reach to its highest level in 2018 that we ever seen before, so before while it is in the launch pad may be this is the right moment to invest.