Starting to feel depressed

Ke
I have been ebf and my son is now 6 months old. I have never had an oversupply but definitely had enough to feed him and have some stored. I would usually get at least 6 - 7 oz per session (most days 9 - 10 oz) and I pumped twice while at work and then nursed him once I was home. I got my period back about a week and half ago and since then my supply has been depleting. This was right around the same time my son turned 6 months and we introduced solids. He still hasn't gotten used to solids so we aren't substituting a nursing session for the demand to not be there because of solids. It's starting to depress me because now I'm struggling to get  3 oz per session. I've tried oatmeal and mother's milk tea but still struggling. I really want to go at least a year because I wanted to avoid formula. Any suggestions?