If things continue like this through July than I certainly won't match June's earnings
Me too, and it will be for the first time in years...
Compared to July 2017, traffic is up, time on page is up, pages per session are up and earnings from AdSense are ... 20% down and extremely erratic, furthermore. IMHO this has nothing to do with GDPR, traditional online advertising seems to be doomed and probably it is.
I tried verything, change units' size, position, number, type; I got more clicks for less money, CPC is 30% down, so arguably advertisers are spending less on display advertising, as simple as that.
This would not that a a big problem for Google, since they can inject as many Adwords ad spaces as they want into their SERP (or, better, as many as a user can tolerate). This is just a web publishers' problem, a big, serious problem, Best way to cope with it is to progressively move from a display advertising monetizantion model towards something different, probably.