If you are not sure if it is ‘a lot’ or ‘alot,’ here is a simple solution: it is never ‘alot.’ That is like writing ‘afew’ or ‘ahundred.’
You are probably confused because you know that English has another, similar word – ‘allot.’ If you are confused, you are highly unlikely to ever use the word ‘allot,’ especially in a Facebook post, so give it up and just use ‘a lot.’
Damn.