Since the verb ‘to miss’ has a few meanings, one might end up interpreting such a phrase as ‘I missed work today’ or ‘I missed class today’. For this, you wouldn’t use ‘sentir falta (de)‘ because that is used to express the idea that you miss something that is not or no longer present in your life. What do you say then? The verb ‘faltar (a)‘!
Ex. Hoje, eu faltei ao trabalho.
Ex. I missed work today.
To say you missed class, just change ‘o trabalho’ for ‘a aula’. Keep in mind that you will also see ‘Eu faltei no trabalho/na aula’, so don’t worry, it means the same thing. Knowing what verb requires something else after it or with it is called regência verbal, in grammatical terms…but that’s another post!
Also keep in mind that if you wish to express truancy/playing hooky/cutting class, you would say ‘Eu matei aula‘, so that’s ‘matar‘ (to kill). Another verb for truancy is ‘cabular‘, as in ‘cabular aula‘, which is more specific although less used.