It does sound like allergy/sinus symptoms exacerbated by anxiety and poor sleep. Also note that just because you’ve have allergies and asthma most of your life, your body will change as you get older. Some people with allergies in childhood ‘outgrow’ them (my brother, who now at 50 says he suspects some are coming back), and some who didn’t have allergies develop them (myself, in my mid-20s).
Since you’ve already seen 2 physicians who came to essentially the same conclusion, I’d suggest starting from there and following through with their recommendations before going to another Dr. The best way to know for sure if they were right is to use your allergy medication regularly, and hopefully they have also prescribed a nasal spray (since they tend to be more effective with eustachian tube dysfunction), which should also be used regularly as directed. Antihistamines are usually recommended to take on an ‘empty’ stomach (2+ hours after eating, or 1+ hours before eating). If they make you drowsy, take them at the same time each evening; or if they make you hyper, take them at the same time each morning – that is if you get the “24 hour” formula. It will take a week or two of consistent use of the allergy med and nasal spray before you feel consistent relief. Many people want to only take the medication when it gets bad, but when they symptoms are persistent, consistent treatment is key.
Optionally, if you do have nasal or sinus congestion, guaifenesin (mucinex) or pseudoephedrine (sudafed – purchased behind the counter) might also be considered – again, be aware of whether they have stimulant or depressant effects on you, and schedule your dosage to as not to disrupt your sleep cycle. This is why I prefer the non-bundled medications (allergy pills or other cold/sinus medications with a ”-D” suffix have sudafed in them, but you might not always need the decongestant).
We are now going into your holiday break, so even though you may want to go out and party, I strongly suggest that you try to establish a regular sleep routine and cycle. In your early 20s, most people still need 8–9 hours of sleep. Recent studies have found that even just staying up late on weekends has a ‘jet-lag’ type of effect on the brain. The ideal is to have a set bed time and wake time that you keep every single day. At least a half-hour before bed time, all electronics should be turned off, as the light shining in the eyes messes with the sleep centers of the brain. Develop a routine of evening grooming, then maybe do some journaling to purge the thoughts and emotions of the day, and/or some meditation to quiet the mind. Set the alarm on your phone to help you stick to a set bed time and wake time every day; you might want to try some of the sound apps to help you fall asleep and stay asleep. Use the holiday break to give yourself at least 9 hours of sleep each night; then when you go back to school if you want to try shorten it to 8 hours to see if that’s adequate, it might be once you have the routine.
If you still have symptoms, or if they worsen, despite being very disciplined about your allergy treatment and sleep routine, then I would suggest consulting an Ear, Nose & Throat (ENT, or Otolaryngologist) for further evaluation, as there are some other conditions that could cause similar symptoms, but require additional testing. I hope you feel better soon!