As brb123 said, what you experienced is very common for your first LD. The next LD you have will most likely be longer, because you now know what to expect (or at least how it feels) when you become aware that you are dreaming.
In my experience meditation has helped increase my focus. Learning to remain calm and stabilize a dream takes practice. The more LD’s you have, the more opportunities to practice, so keep doing whatever you’re doing. Also, try to be patient 
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If you haven’t looked at the tutorial on Prolonging Lucid Dreams in the FAQs and Tutorials section, also take a look at that.