My "I miss you very much" was not accepted, Duolingo wanted me to write "too much" instead. However, "too much" would have been "demais" ... come on Duolingo, be decisive!
Mine was "I feel your absence a lot". The hints don't have 'to miss' under sinto.
Your translation, or the more literal alternative "i feel a lot your abscence", should help people to remember how the original sentence was constructed in Portuguese. The translation is more a translation of the feeling the sentence is trying to convey than a word-by-word translation. Once you understand the construction, it helps you to translate similar sentences in either direction.