Hello. Thank you for coming to JustAnswer with your question, and welcome.
If you have a sinus infection, you should see your doctor for treatment. There is not much in the way of over-the-counter medications that is safe to use. For sinus and cold symptoms the only OTC medicines you can use are acetaminophen (Tylenol) for pain, and cough syrups that contain only Guaifenesin (an expectorant that thins secretions) and Dextromethorphan (a cough suppressant).
Do Not take anything that has a decongestant in it, as these may impair blood flow to the placenta. So be sure to never take a multi-symptom cold reliever.
For an infection you will need an antibiotic, and your doctor is the person to ask about any other medications you can take during your pregnancy.
Until you see your doctor, make sure you are getting plenty of fluids that will also help to keep the secretions thin and more easily expelled. Saline nasal spray can provide some temporary relief, and you can use it as often as you like.