Hi. i have a funky rotten sweet sweat smell in my nose and constant "congestion" feeling.

Sinus infection?: It sounds like you may have a sinus infection. Try using nasal saline several times a day or using a neti pot. Decongestants may also help or antihistamines if you think this may be related to allergies. If it persists for more than 3 weeks then see a doctor since you may have an infection requiring antibiotics. I hope you are feeling better soon.