My chihuiahua poops inside?

I have a 5 and half year old chihuahua who is lovely on every level except she just keeps doing her poops indoors alot. im soo mad now i sometimes dont see it and walk in it. grrrrr like today.shes only 4 pounds so her poops are tiny but she does them indoors but does her pee pee ioutside?? she will do her poops outside when im walking her? but when shes home she dont go in the garden to do poops. im so annoyed!!!!! I dont have any money to pay for someone to come out so if someone could give advice here i would be so grateful.