I had a time of grumpy-itis about 8 years ago. Mine was caused by stress. A lot of things all happened the same year one after the other. By themselves they were nothing but together they were overwhelming.
The eyeopener came when DH & the lady that worked with us kicked me out of the store for being grumpy. Told me to go do something enjoyable for myself.
I was lucky in that the local 2-year college offered a stress management class. It was one on one for 10 weeks. It did help me and I still use what I learned. Have to add that it reminded me a lot of Lamaze but without a coach.