Hey there, sorry to hear that you're not getting any joy with sertraline. But, there are several options available if you discuss the ineffectiveness you're currently experiencing with your doc.
Apart from increasing the dose, you could be switched to an alternative SSRI or to a med from a different drug class. There's also the possibility of using add on therapy such as Mirtazepine which is quite a commonly used treatment strategey.
But, as already by others here
@Ljt , make an appointment with your doctor to discuss who you've been feeling and how you feel that Sertraline is not working for you. Quite often, it can take several attempts to find the right med which suits you because naturally, different people can respond differently to medication.
Also, I was wondering if you have been or even considered some form of counselling/therapy? As quite often a combined approach can at times produce more effective results.
Take care, and hope a change in your current med regimen will help you.