you're correct, you don't need to mark the end of these words with a dot at the end of them.
acronyms (asap, fyi, lol and such) don't necessitate dots, with the exceptions of e.g. and etc. (you need to put dots where i've put them).
with math or maths, photo, info and the others, these are shortened forms and built into the language without dots.
with months, you can either choose to put a dot (Nov.) or not (Nov). both forms are correct.
with days, when you use the shortened forms, you don't need to put dots (Sun, Mon).
rules vary in each cases, so it's best if you pick up this knowledge as you meet them in authentic materials.
Do I need to use a period after the abbreviation: info (information) & ASAP (as soon as possible)?
- You don't need to put period in info and ASAP. However, when it's for formal writing, avoid using abbreviations.