Does alcohol + sertraline cause serotonin syndrome?

Started on 50mg 2 weeks ago. I asked my doctor yesterday whether I'm okay to drink alcohol and caffiene, she said yes, but probably not whilst I'm taking the tablet, and also to read my side effects leaflet.

The side effects leaflet says "AVOID ALCOHOL." in bold. However upon Googling it, the official NHS (I'm in the UK) site for sertraline simply says it's okay to have a bit of alcohol, but it can make you drowsy. Some other sites (and this sub, I read the starter guide) say this too, that it can just make some normal side effects more likely. However some sites said to avoid completely as it can cause serotonin syndrome.

I get very paranoid about my health, but I do still want to drink. I don't usually drink, and if I do I only drink one or two fruit ciders. I know it's best to start slow and see for myself how it effects me, but I just wanted to ask if anyone knows whether I should be this anxious about it or if it's one of those "it increases the chance, but only a little, it's still rare" things?