I have missed you = Tu m'as manqué
The thing is that French and English are two different languages. So, one cannot always translate literally. Actually, there is nothing to understand to it! It's just the way languages are: French have it way to say things, English has it own way, too.
There are what we call in linguistics “deceptive or false cognates” that cause confusion. They are words that look the same, but have a different meaning. For instance, eventually does not mean "éventuellement". Eventually means that it will happen, but later, while "éventuellement" means that it might happen. "éventuellement" means maybe.
Another one is "digital". In English, the word "digital" comes from "digit" which is in French "chiffre". So, a "digital amplifier" for instance, will translate "amplificateur numérique", numérique with the idea of numbers, digits. In French, "digital" is a derivative from the word "doigt" (finger). So, "empreintes digitales" is translated by "fingerprints".
So, I've missed you will translate by “Tu m'as manqué”.
So, enough confusion for tonight.
Enjoy!