Feels like throat/stomach is burning?

I have been on Sertraline for about a month now, and I missed about 4 days of my doses because my boyfriend lost 4 of my pills, I got my them refilled yesterday and took one at around 1pm, when I woke up this morning I felt super sick. Felt like there was something stuck in my throat, my stomach burns, it feels very acidic. I need to take my dose today but I'm scared to eat anything and take it again. Is this something that happens with Zoloft or is it something else? Maybe stress? I barely eat anything. I did eat ice cream yesterday and I am lactose intolerant but it never really feels like this.

When I use to take celexa I would get a burning in my throat and never connected it to celexa. The pharmacist told me it is a reflux from the stomach:  it finally went away but I took Rolaids and tums to help.