Is your hair also dry?
Assuming the hair isn't irreparably damaged, try a protein treatment (will help with droopy curls) followed by an intensive deep treatment.
Do you know any of your hair properties, so I can offer a more specific recommendation? Things like porosity, strand width (fine, med, coarse), etc.
By the way, "only washing every 3 days," is not particularly descriptive. What products are you using? Low-poo? Conditioner wash? Sulfate wash?
Hair Type: 3c, Med-High Density, Low Porosity
CG since '09
Low Poo: KC Come Clean
Condish: AOHR, TN (Avocado), TJ Balancing Moisture
Leave in: GDL, KBB
Curl Lotion/Gel: CHS/CK
Others: CJ Curl Rehab, Jojoba Oil