Any doctors or nurses?

I work so much It's so hard to find time to go to the doctors and my boss is horrible and pretty much won't give me time off to go!
I was there last week because of a chest infection and they gave me antibiotics I was allergic to now I've been taking a new course of antibiotics because they changed them now I have a burning sensation in my stomach, the only time it goes away is for about half an hour after I've eaten but even then I still feel sick ! 
I'm just wondering if it sounds like a side affect of the new course of antibiotics or something worse like a stomach ulcer! 
I'm so worried! 
*UPDATE*
I'm on erythromycin 250mg 
Taking 1 tablet 4 times a day 

Glow Resources

Let’s Glow

Glow is here for you on your path to pregnancy

Glow helps you navigate your fertility journey with smart tools, personalized insights, and guidance from medical experts who understand what matters most.

25+ million

Users

4.8 stars

200k+ app ratings

20+

Medical advisors