Scared to start Mirt

I've been on antidepressants for about 13 1/2 years now, after living with untreated depression and anxiety through most of my life. I was on Zoloft for about 4 years until it started pooping out on me. I was then on Effexor, Wellbutrin (a nightmare), Effexor again briefly until I started Lexapro. This was good for me for about 4 years, then I started feeling the lack of motivation, constant blahs, sleepiness, and anhedonia. I felt like I was sleepwalking through life without really feeling or fully experiencing anything. My anxiety was also kicking up. My psych added buspar, but thought I should keep the Lexapro. Buspar helped with anxiety, but I still felt flat due to the Lexapro. I finally pushed to get off of Lexapro in January and she recommended Viibryd. I did a slow taper off Lex, onto Viibryd (kept the Buspar). I didn't really notice a tremendous difference in mood while on the lower does of Viibryd, but had vivid, anxiety-producing dreams, bad sleep, and horrible night sweats. When I hit 20mg, my anxiety ramped up to unbearable levels. Literally everything triggered anxiety, anything I read, listened to, watched, people I talked to, etc. I would literally just sit and stare, trying to fight back the anxious thoughts. I felt hopeless and terrified of the future, and suicidal ideation started last weekend, so that was it. I called my psych and told her that this was not for me. She strongly feels that mirtazapine is the right drug for me, but I'm so gun-shy about trying a new drug after Viibryd being a nightmare. I called her the next day and asked to just go back to Lexapro until our appointment next week, and she agreed to call in a 10 day script for 10mg (was on 20mg when went off). I expressed my anxiety about the vivid dreams and weight gain, but she seemed to downplay these as "rare", but we'll discuss further on Thursday. So, I'm currently on 10mg of Lex, 15mg of Buspar a day. Feeling much better than I did early this week while still on Viibryd, but obviously still not great.

So, I guess my question is, has anyone gone from Lexapro to mirtazapine successfully? Other than the sleepiness and perhaps slight weight gain (<5lbs), I didn't suffer much in the way of side effects with Lex. I'm mostly looking for my anxiety and depression to be controlled without feeling drowsy or manic. I feel like with the double-whammy of depression and anxiety I have to choose between my depression being treated, but feeling hyper/manic with bad anxiety, or having my anxiety under control while feeling tired and emotionally flat.