I am a master's student in 3rd world Asian country. My master's thesis guide (who was from a different institute) abandoned me after giving a research paper to read. Now, with no guidance left as no-one in my institute works in X-number theory, I began reading the papers related to the first paper. I read 5 papers in total and in my thesis I will write in detail about the details which were not covered in the papers (like detailed steps and proofs).
But, as I had no help I posted questions on mathstackexchange and some which were not answered on MSE were subsequently posted on Mathoverflow. I am really thankful to the community because without their help it wouldn't be possible to completely understand the papers. One professor in Y- number theory (who recommended me to another professor) agreed that I could write his name as a supervisor (my institute has rules that he had to be made a co-guide earlier even when I didn't know my guide will not work with me).
I don't want to write in my master's thesis that I took help from Mathstackexchange and Mathoverflow because it could create an impression that I don't know enough mathematics. But if I don't acknowledge it, is this plagiarism? It doesn't seem right that I write the names of all the users as I have asked about 10-12 questions there. I think writing all those names will create a bad impression of me. The evaluators in my university may not understand the situation. I have worked really hard on thesis despite the trauma of my guide not replying to any of my email.
Can anyone please tell me whether I am plagiarising?