meds stop working? I am worried?

I have been on a new antidepressant for a while and recently noticed a drop in energy and unable to sleep. I am so scared because things were going so well in the past few months and I don’t know what happened to the meds. Did they stop working? Omg, will I need to be in this cycle again? I feel anxious and I constantly think about this and how to proceed with this during work / free time.

what can I do??