That does seem unlikely. If there are 5 million PoGo players active enough to get 11 evolution items, only two or three players should get exactly 6 in a row, then 5 in a row. (Odds go up a bit if you include those who got at least 6 in a row, then at least 5 in a row, and odds go up more if you include people who have gotten more than 11 total.)
If it is random, then there might only be a handful of others out there who could share in your bad luck.
Personally, I've gotten 20 total so far:
3 Sun Stone
4 King's Rock
8 Metal Coat
3 Dragon Scale
2 Up-Grade