Dora, I haven't worked seriously on this piece, but I have played other Chopin etudes that had much bigger intervals than this one, and I have small hands too, so perhaps these general suggestions might help.
Nearly all the fingerings in Chopin editions are editorial and should not be viewed as authoratative. If a stretch feels really uncomfortable, it will cause tension and loss of control. In that case you should find the fingering that feels easy, even if the fingering is a little odd. For example, if using 4-5 for the top notes of a series of doubles causes strain, try using the 5th finger for both, 5-5. Actually, it is your teacher's job to teach you how to find the right fingering for you. If he/she is insists that you follow what is printed, that is a bad sign.
Keep in mind that the pedal is freely used in this etude, so you don't always have to make a perfectly connected legato as written.
Make sure that you upper body is properly placed so it can support the doubles when they ascend into the high register.
Good luck with this piece. It is one of the most beautiful in the entire repertory.