Hi there, I agree that it could be that your Eustachian tube is still blocked. Often, after a bad bout of the flu or sinus infection, there is residual congestion and inflammation which takes a while to clear. Your prolonged illness could also explain the leftover lethargy, because your body needs a bit of time to recover from the stress of fighting the infection. I would recommend continuing with some antihistamines with decongestants like loratadine/pseudoephedrine or tripolidine/pseudoephedrine even when there is no nasal congestion. This is because it will help to bring down the inflammation around the nasal passages and Eustachian tubes, hopefully enough for it to open up. Nasal sprays also help, you could try short-term decongestant ones like oxymetazoline, or steroid ones like mometasone if you are prone to allergies. Get help if your ears are starting to hurt or you develop a fever, because blocked Eustachian tubes can lead to middle ear infection. This will unfortunately require antibiotics yet again, but hopefully you won t progress to that stage. If you remain blocked even after two weeks or so, you might need to see an ear, nose and throat (ENT) doctor to see if any other steps would be necessary. This may include inserting tubes in the eardrums to relieve the pressure. In the meantime, make sure you get enough rest to give your body time to recover, and drink at least 2 litres of water in a day. Hope this helps, and all the best to you. Regards, Dr. Teh