About 8 days ago, I switched from mirtazapine to prozac, as I was feeling tired all the time. I'd been on 30mg of mirtazapine for a couple of months and the doctor said to do a straight swap. Is this the best way?

For the past 4 days I've been feeling sick constantly, I haven't been able to eat properly and unfortunately lost weight again. I've also been feeling a lot more anxious, dredging up old thoughts, and I had a weird anxiety thing (I wouldn't call it an attack exactly) 2 days ago, ringing my friend in a bit of a state.

I don't know if this is withdrawal from mirtazapine, start-up side-effects of prozac, or the mirtazapine was helping me more than I thought.

I can't see my doc for a week now, so I don't know what I should do. Should I stick with the prozac? Could I take the 15mg mirtazapine I still have in addition to help my appetite?