When will mirtazapine work?

I, too, have taken Lexapro for several years. In January I experienced a third MDD. I guess the low dosage of Lexapro wasn’t working any longer. I fell into a low with pretty severe anxiety, depression, and weight loss. I tried Prozac which made anxiety much worse. Then, my GP prescribed Mirtazapine. I started out on 7.5, then 15, then 30mg. I felt that the 30 was too high for me, so I’m now taking 15mg/night. My depression is lifted but I’m frustrated about the nervous anxiety that plagues me beginning in the morning. I do take clonazepam for the shakiness, trembling, and stomach tension. I use it at .125mg at a time and then add throughout the day if the anxiety returns. Usually needing less than .5mg total. I don’t know how long this anxiety will continue, or if it will subside given more time on the Mirtazapine. I’ve been on Mirtazapine for 3 months now. Any suggestions or questions that I should ask my doctor?

Hi, OldSal! Most antidepressants including mirtazapine take about 4-8 weeks to become fully effective and anxiety takes longer to treat than depression.
It's not unusual to have to try several medications to find the one that works best for you. It's good that you want to stay on this medication because you need to give it a "fair trial" of the 4-8 weeks.
Try to be patient and keep a positive attitude. At very least right now you're getting a good night's sleep which is essential for good mental health.
Best regards,
Wildcat
PS, what you describe could possibly be discontinuation symptoms but more likely are side effects of the mirtazapine which generally resolve on their own except for the tinnitus. Report this to your doctor as it can rarely become permanent.