Severe nausea after being on citalopram for 11 weeks

I am on week 3 of 20mg. Started on 10 for 4 weeks, 15 for 4 then 20 so it’s been 11 weeks in total. I started getting nausea on and off a couple of weeks ago but for the past 3 days it’s been constant and severe. Have been to drs and have been given cyclizine but I don’t feel it’s helping.

This has coincided with my anxiety actually decreasing at long last. So I’m wondering if there is some connection in the serotonin causing the nausea. I have googled and there seems to be a connection between serotonin and nausea. Does anyone have any experience of this and if so how long did it last? It’s unbearable at the moment and I’m worried about going back to work on Tuesday. I have been on citalopram before but don’t remember this happening.

Thanks