um horror de me ter

17:19 Jan 9, 2019 

I'm looking for a concise translation that fits in with the rest of the poem. I don't foresee replacing "horror" with another word that takes much more space. There has to be a balance as far as the length of the lines in the poem; this is not prose. I thank you all for the suggestions / comments (which were very helpful as a starting point, by the way), but I'll stick to my own interpretation after consulting the Priberam and further analyzing the poem. Among the meanings of "ter" as a pronominal verb, two caught my eye:

17:12 Jan 9, 2019 

18. Segurar-se, equilibrar-se.
19. Parar, conter-se, deter-se, manter-se.
https://dicionario.priberam.org/ter

It seems like they both make sense. With #18 he's probably referring to his difficulty in keeping the balance when he flies (in his imagination). A possible translation might be "a horror of flying on my wings" or something along those lines. With #19 he's clearly talking about his horror of feeling self-restrained, which is very apropos on the subject of freedom. Here I can think of two options: (1) horror of restraining myself, or (2) horror of self-restraint. Initially I had thought of "control", but "restraint" seems more pertinent. I'm leaning towards the latter, since "ter-se" could be short for "deter-se" or "conter-se". (Pessoa was a master of language disguise.) This interpretation is also in line with the famous "Multipliquei-me para me sentir...": http://www.mpbnet.com.br/caro.murgel/textos/fpessoa.htm Here and there Pessoa refers to the idea of overflowing ("entornar/extravasar"), and this is an indication that he cannot be self-restrained or else he wouldn't be the great poet he was. Please feel free to add any new insights you may have. Thanks again!