these numbers have their "BASE" meaning.
I understand 555 as changes are happening, and 888 abundance is on the way.
But, you have to understand that it is your Higher Self/Angels, which is/are sending you these messages, in response to your thoughts or current vibrations.
So when you see 555 then try to keep positive outlook by concentrating on being Happy or doing things that makes you happy.
555 does not mean that you will see a change immediately, because it may involve others which will benefit first, but be sure that you will be among them, later in time.
when i see 888, i mentally tell to my self, "Great abundance is on my way", and "Thanks"
Whenever you see these numbers, try to recall what you thought 1~5 or 10mins ago. Then try to combine the thoughts with the meaning of the seen numbers.
I use "Angel Numbers 101, by Doreen Virtue - IOS app" for the meaning of the numbers. (here
are the sequence numbers explained but on that page, the numbers have a slightly different explanation than what the app is showing. )
But there are other
sources for the meaning of these numbers.
But always remember that there is something, which is sending you these messages (in my current belief, the source of the message is more important than what these messages means or whatever outcome they bring, so i try to give mentally thanks to the source).