For me, spiders are about creativity. Of course, that's just what they mean to me. The fact that they are getting larger could be that they are 'really' trying to get the message to you to take your creativity seriously. Maybe they are doing the spider version of 'yelling' to get their message heard.
I'm not certain what the white spiders are about specifically. When you are creative, do you tend to be on the spiritual side with it? Or perhaps they are suggesting that you become more spiritual with your creativity? Just some suggestions to hopefully help spark some answers for you.
Have you ever read Ted Andrews book 'Animal Speak'? It might be interesting to see what he has to say about spider. You can also search for the spiritual meaning of spider on Google.
Hope this helps!
Blessings