advice from other working moms

So I've decided to go back to work because I really do miss working. My husband told me I could stay home with our son as long as wanted and never had to go back to work if that's what I wanted. My son is 4 months old now and I started itching to go back to work. I quit working in August and had my son in late October.  I truly love and cherish every moment being with my son, but I love teaching. I already have 5 interviews set up. As I went into my sons room tonight to rock him and nurse now I'm kinda regretting making the choice. Any working moms have any advice?