Doxycycline (std) partner cheated

So my partner cheated. I’ve only ever been with him and I’ve been prescribed doxycycline. So far it’s been an hour and I feel fine cause I had a hearty meal. Enough to make me full. Not noticing any side effects. Maybe my body is tolerating it well. Have any of yal had a partner cheat and caught chlamydia and ever been on doxycycline for any reason? I’m scared I’ll start having side effects.. can’t remember the last time I was on these pills tbh or if I ever had bad side effects. I wanted to hear from yal