well that too is a good question, muser. "how do we know we are loved/not loved?" humm. one of the ways to know we are loved is does the other person show in their deeds that they value us in their life? in other words actions speak louder than even words. (you know my situation with family so that is a question i had to ask myself recently.) there are different degrees of love. but of course you are worthy of being loved!!! what i've found is that it's like a scale...meaning where are the other person's priorities and where do i fit into that list? so often times we are loved just not to the intensity of other ppl in that person's life. but we are all worthy of being loved unconditionally i might add.
if you received an apology it sounds as tho that person cares very much for you. we all make mistakes. perhaps they realize they did. so then you can rely on trusting them to a degree. benefitting from what you now know, you can be cautiously optimistic they are sincere. in my case i've determined without an apology from the other person and their ongoing unexpected hurtful behaviors that i choose to not expose myself to this person because they do not value or respect me. i do not want to be blindsided again. but that occured over a long period of time and experience with that person.
in your case it may have been an unintentional error on their part. i'd give them an opportunity to continue being around you. just be cautious so you do not expect too much in return.
but never forget your value in this world!!! there is only one you and there is so much to be loved. just surround yourself with ppl that love you unconditionally as you do them. that is the key cause we're all human and make mistakes.
hope this helps you.
ps sorry for the long post!