I've noticed my girl has become less affectionate the more serious we get (almost a year together, have discussed living together, kids etc).

This isn't a huge problem, perhaps just the honeymoon phase ending? She tells me she loves me all the time.

We did a love language test, hers is acts of service, mine is physical touch. We had an argument last week and I told her that sometimes I don't feel loved, she got offended and the next day she was SUPER affectionate and loving, perhaps the idea of losing me was going through her mind because of the argument.

Just wish she was as affectionate as she was in the early days of the relationship.