Baby blues at 13 months?

Hi, I'm new here but looking for reassurance that hopefully what I'm feeling is normal... 

My little boy is 13months old and doing so well. He's thriving, healthy and progressing at a normal rate, I on the other hand feel like I'm going backwards and wondered if I'm only now truly going through the baby blues?

I had to go back to work when he was 4 months old due to financial struggles, unfortunately I had to go straight back into full time as my employer didn't accept my part time hours. He goes to nursery once a week and is with his dad and grandparents the rest of the time.

Lately I have become extremely protective over him. I cry when I leave him, I don't like anyone going out with him in fear that something might happen. I'm used to him sleeping out as he sleeps at my mums every other Thursday and I know he's safe as I trust my mum the most out of everybody. But when it comes to my husbands mum I'm the complete opposite, I don't like her leaving my house with him, my husband and I argue about it all the time but I can't change how I feel and constantly feel like I'm being backed into a corner to justify what I choose to do with my baby. I am made to feel like I'm being silly or awkward towards her but he's my baby and I can't help how I feel. I don't know how to shift this feeling and what to do to help the situation?

I though baby blues was in the early stages of having a newborn but everytime I read the symptoms it's how I'm feeling now. Did work cover my feelings for a while? Am I paranoid over something that might never happen? I don't know, I have all these questions coming at me and I have no answers for them.

Someone please tell me its normal and everything gets better?