Yesterday, I could get 1kg of sugar for $1. Today, I can only get 0.75kg of sugar for $1.

My dollar is worth less (can be exchanged for less goods) than it was before - I'm pretty sure that's inflation.

The word "inflation" has several different meanings. You're talking about consumer price inflation. There is also monetary inflation, which is the supply of money plus debt (marked to market). Those are really completely different things with only a very loose relationship.