I'm interested in hearing what his response to your clarification was, and if you're both now on the same page. Are you feeling OK about the situation now?

You don't sound like a disposable person at all. Anyone who values friendships would value someone like you. The fact that you sent your online friend cards/flowers shows how much you care. People who care are actually quite hard to come by these days. Try to think in more positive terms about yourself.

What is it about the way she acts that makes you feel as if you don't exist? Maybe she's going through a hard time too, but isn't the type to communicate that. Losing people you love is hard; losing them abruptly and in such circumstances is something I wouldn't even want to think about. Can you imagine how something like that could impact your life? Things you said or didn't say, regrets, plans you had together, etc. Everyone deals with situations differently, and some better than others. Her not talking to you as much doesn't mean you're less of a person, or disposable. It probably has very little, if not nothing, to do with you.

I'm not sure it's a good idea to form close relationships with work colleagues. I imagine it could cause issues in the future. If he is someone you see outside of work (meaning, he is your friend by choice, and not someone who is forced to interact with you due to work) then MAYBE? I don't know. Maybe someone else here can offer some advice.