Hello Cel,
First welcome to the forum...I agree with everyone said you should talk to your husband tell him what you feel...maybe he thought you are ok but you are not...I have also 3y/o boy. Before i was feel the same, what i did i talk my husband i told him i want to do part time job..He didnt say yes but he dont have a choice...I want to have a break as the same time i earned money for myself...Let him look after your son during weekends....
During week days try to go for walk in the town im sure alot of mother's and toddlers group around let your son play and you can chat with other mummies and make friends....