Last month Adsense revenue was fluctuating quite a bit (some days $30, some $80)... This is why I think 3 advertising streams works best to keep a consistent pay check coming in.
YES, but this won't happen in 2-3 month. Keep working and you will get your cheques bigger and bigger.
i believe your site have group of followers. during the first week you put the adsense, they notice it is something new on the site and everybody clicked on it.. after sometimes, more people know it is add link and dont bother anymore.
Oddly enough my sites are beating traffic numbers but eCPM has beeing cut to half (more or less). Are people paying less for the ads? Did google changed anything that caused this?
promote your site by SEO, link building there are tutorials here in DP about promoting your website..good luck