It's natural for emotional extremes to bring tears. A few years ago when I was going thru "the change", I had extreme mood swings. I'd cry at commercials, if someone was randomly nice to me, anything remotely emotional. I find it funny now, but at the time it was exhausting. I'm pretty much back to normal now...for me.

As a general rule, crying is cleansing, both emotional and physical. It does feel good to just cry sometimes. Just like anything else, if it is causing you distress or affecting your life, tell your doctor.