If you're watching the price of bitcoin at the moment then you should neither gamble or invest atm. Just keep hold of your coins & ride this train to $5000 per bitcoin 
but if you really think that bitcoin will go to $5000 why not invest more money into bitcoin?ì investing now it's the wise decision gambling is not, i only gamble when i win money or get them for free, otherwise i prefer to invest in altcoin or bitcoin or mining, either one of these are very remunerative in the long run, but i admit that gambling can be remunerative in the short term if you are really lucky, my advice is to gamble 10% if you can afford to lose those money and keep the other for big investment