If your gathering class is only lvl6, then you can't expect to make much gil. You can make some gil, sure, but not enough to support a full-blown character. There are many ways to make gil, but there is work that needs to be done before you get to the point where you can make a good amount of gil. If not we'd all be rich by lvl6.
Here's some tips to maximize your gil, tip #1 STOP TELEPORTING - Until SE fixes the horribly over-priced teleport fees or brings back anima then start chocoboing or airshipping everywhere, the amount of gil you can save by doing this is very significant for low/mid level characters (anima would be the BEST solution, hands down.) Tip #2 - Stop binding gear and sell them in the marketboards - Here's what you do, check online or in the app to see what rewards you will have to choose from in all the quests you plan doing that day. Then check all the marketboard value of each gear/weapon/reward for the quest and sell those pieces. You can make an easy 50K or more just by selling the rewards of quests lvl1-20, if you do the proper research, which means also checking how often things sell versus how many are up versus how much you can overcharge before it won't sell. Tip #3 - Farm drops - Check the marketboards to find out what sells quickly and for a lot of gil, then kill tons of those mobs as your highest level job. Remember, the goal is the drops, not to gain experience for a lower level job. Tip #4 - Similiar to tip #3, do some marketboard research to find out what synthing supplies are in high demand and selling for a giant profit, then synth what sells. Tip #5 - get to a higher level than 6 before losing hope/panicing. lol