See your ENT. If this is a recurring problem you should see your ent. He can tell you if you have recurrent sinusitis, allergies, migraine headaches or another problem. Definitley never use afrin (oxymetazoline) for more than 3 days, you will get addicted!
Antibiotics. Headache with fatigue... Sounds like more than allergies. You may have a sinus infection. There are some good over the counter meds you can try. Tylenol (acetaminophen) sinus. You can also add some saline nasal spray and some afrin nasal spray (short term use - 3 days). If it doesn't get better in 7-10 days, you may need some antibiotics.