Changing Medications and Feeling Scared

My medicine is changing from cymbalta to trintellix. I'm scared because I've had severe allergic reactions to some psych meds before. It doesn't help that everyone says weaning off cymbalta is difficult. I'm hoping to ask my psychiatrist if I can try rexulti with the trintellix. I used to take buspar with the cymbalta for my anxiety, but it stopped working. I'm just scared of being sick for months like I was the last time I went through medication changes.