Oh Sam la Tricoteuse I forgot to answer your comment! Mono - and allergies - and sinus infections - oh that's terrible! I understand your frustrations. For the sinuses Sudafed is a miracle worker, as is steaming (gently boil water and breathe the steam in through your nose, or even better buy a "spa facial" steamer cheap from Wallyworld). This will help get rid of future infections as well, since you want to try and avoid giving antibiotics as much as possible now she's allergic to one. This makes her susceptible to others and it's best to leave that for a worst case scenario.
For the mono, the immune system is hard up for YEARS after infection, so taking lots of vitamins helps. Seriously! I've been suffering as of late from residual fatigue and other infections from reduced immunity (they say it takes up to 5 years to get completely healthy again) so I started to take a full multi-vitamin every day. I've been doing it for about 4 days now, and I feel WAY less tired during the day, and have actually been getting and needing less sleep each night!