Come to me, my melancholy Baby

Did you ever have a day where you just feel like you could cry at the drop of a hat? No real reason, just having a "blue" day. Today was one of those. Maybe it was the conversation with my neighbor when she pointed out that I was referring to my mom in the past tense (even though she's still alive)and that maybe I had accepted the fact that I had lost a large part of my mom (due to dementia). I haven't accepted it; it just feels like she's gone. Maybe it was the fact that I am constantly thinking of my dad who passed away 5 months ago, especially today when my son was competing with his tennis team for the State Class B title (my dad loved tennis). Boo hoo, they lost. Or maybe it was the fact that any conversation with my 20 year old always is a struggle to not become adversarial. The simplest comment is always met with defensiveness or even worse, the attitude of "that was simply the stupidest comment ever". I guess at 20, they know all and I know absolutely nothing.
So here I sit at a computer which will let me type out my feelings and not give me a wisecrack remark or tell me to get over it. It will quietly not comment while I pour out my feelings. Maybe I'll even give in and let myself have a good cry. Is that wrong? I don't know. How long is a cry allowed to go on before it's considered wallowing in self-pity? Tomorrow I'll count my blessings, but tonight I'll just hug my box of Kleenex.