B.C.
Your son is perfectly normal and doing what babies do.
You - on the other hand - I'm worried about.
Crying a lot on your own, worrying your child doesn't find you fun anymore, feeling extremely sad.
My son was 18 months old when I was having a check up at my doctors and I was telling her I was so tired all the time.
She was joking with me and told me "Well you need to get more organized" - and I bit her head off.
I ran down a typical day for me from 4:30am to 10pm in 15 minute increments, told her I'd organized the hell out of my life and HOW THE HECK COULD I ORGANIZE IT MORE.
The long and the short of it was I was depressed, and trying to be super Mom and not seeing what I was doing and I felt I could never stand down, not for one minute, ever.
6 months on a low dose of Zoloft helped me so much.
After 2 weeks it felt like the hair on the back of my neck wasn't standing on end all the time.
I learn to let some things go, and relax and have some fun (who cares if there are dishes in the sink? They'll be there when we get back. We're all leaving it and taking a day at the county fair and have some fun, etc).
Please see your doctor and talk about your sadness and crying jags.
Getting your depression treated will have you enjoying life and your family again.