The thing that is happening is that we have diferent communication tasks: The first one is to expres an emotion but in past as a situation: temía que me despidieran. When you talk about a feeling related to someone else actions you use subjuntive, in this chase is a past situation so you most use the "subjuntivo imperfecto" with the action that cause you a feeling. The next thing "si me oponía" is refered to something real, at least for the one who is talking. Look at this: "si me oponía me despedían" or just the same: "me despedían si me oponía". Summarizing: a conditional sentences in accordance with the reality uses indicativa, just like the last exaple. To express a feeling uses subjuntivo just likein the beggining. The sentence you chose merge both functions. I hope I've helped.

Hi Weston. In this case "si me oponía" is in indicative because it is a Conditional sentence. In Spanish the - if clause - can be conjugated in several ways depending the nuence you want to give to your ideas. "Si me oponía" can be followed by a complement such as: "Si me oponía, me habrían despedido". This Conditional sentence is constructed by: "Si me oponía" (pretérito imperfecto de indicativo) + "me habrían despedido" (condicional perfecto). Another way is to say: "Pensé que me negarían un aumento si me oponía". "Pensé que me negarían un aumento" (condicional simple) + "si me oponía" (pretérito imperfecto de indicativo). Best Regards.