Very Sick - Medications

I'm 15 weeks pregnant and got sick several days ago. It's definitely bronchitis or a bad sinus infection because my whole upper respiratory system is swollen (major tightness and burping for no reason) and I'm coughing up mucus like crazy. Belly hurts from coughing. I went to a walk in clinic and they gave me a zpak and told me I could take regular Robitussin. I just feel so worried about the meds now and I'm still feeling awful. How did your pregnancy illnesses go? I just need some input from others.