I thought I had gas giants being mined it was running out of fuel that was the problem.
Bear in mind that to generate fuel, you don't just need to mine a gas giant, you need to mine a gas giant (or gas cloud) with an appropriate resource deposit - Caslon if you're using Basic Space, Fission, or Quantum Reactors, and Hydrogen if you're using Fusion, Hyperfusion, or NovaCore Reactors. Your freighters will then pick it up and bring it to space stations and colonies, and ships can refuel from any location which has surplus fuel stocks.
It is also possible that you have more than enough fuel production and that the cause of your fuel issue at the homeworld is simply that your freighters are slow. If your fuel source is a gas giant on the opposite side of the system from your homeworld and your freighters do not have a hyperdrive of some description, then it will take a very long time for your freighters to bring fuel to your homeworld as they have to crawl across the system at their sublight cruise speed of probably about ten (assuming you use the default designs, though you'll probably not do much better with custom designs in the very early stages of the game), whereas even an underpowered Warp Bubble Generator will probably hit a hyperspeed of 600 or so and allow your ships to cross the system relatively rapidly. Especially for freighters which lack hyperdrives, there is also the possibility that your freighters will run out of fuel on the way to or from the gas mining station, which reduces their speed to about one third of the normal cruise speed and may make it impossible or very difficult for your ships to arrive at the gas mine or the homeworld, as orbital speed in the game is somewhere around 3 or 4.