What did Ya'akov mean when he replied "You know how I worked on your behalf? How did this counter Lavan's statement?
Seforno: Ya'akov was saying that he should stop ascribing his successes to divination, which is rooted in Mazal, but rather to his (Ya'akov's) hard work, borne of experience, and intense efforts. 1
Ramban: Lavan knew well how hard he (Ya'akov) had worked for him. 2
Bechor Shor: This is a reason to give to me a big wage. (Also, when will I do for my family?!)
And what did he mean when he added "and what your livestock were with me"?
Seforno: He was referring to the way that he had bound the animals with broken limbs and healed those that were sick, as befits a good shepherd.
Targum Yonasan: He was reminding Lavan how well he had looked after his sheep.
Rashi: He was asking Lavan to recall how few sheep he had handed him (and to note how many they had now become). 1
Ramban: Ya'akov made three statements here: He reminded Lavan 1. How hard he had worked for him; 2. How long he had faithfully looked after his sheep; 3. How the few sheep that Lavan initially handed him had proliferated - thanks to Hashem's B'rachah.
See Ramban, who queries the order of the wording in the Pasuk according to Rashi.
רש"י: ואת אשר היה מקנך אתי - את חשבון מעוט מקנך שבא לידי מתחלה כמה היו: לכאורה לא מדובר כאן על מספר הצאן אלא על אופן הטיפול בהם?
גור אריה: כבר כתוב לעיל (פסוק כו) "את עבודתי אשר עבדתיך" ומה הוסיף כאן? אלא שני דברים אמר לו- עבדתיך בכל כוחי [בפסוק כו] וצאנך היה מועט והוא התרבה [בפסוק זה].