I realized that even through lacross was fun, I have sacrificed too much on hockey.

// this is the main clause:
I realized [object].

// this is a subordinate clause:
I realized [that even through lacross was fun, I have sacrificed too much on hockey].

within it is another subordinate clause:

that [even through lacross was fun], I have sacrificed too much on hockey

Therefore, it is

1 main clause, 2 subordinate clauses

Sentence Structure in detail

I realized [that…]. (main clause)

noun clause as object (subordinate clause) – that…I have sacrificed too much on hockey

adverbial clause of contrast (subordinate clause) – even though lacrosse was fun