You're doing it tough by the sounds of it; I'm sorry to hear that. I'm not sure where you are in rural Queensland but my first piece of advice would be to connect with you GP. I know it's difficult when you have young children to find this time for you, but for their sake and yours, please try. Anti-depressants are not for everyone, but as the previous commenter noted, they can be extremely helpful and this is a conversation you can have with your GP - it doesn't have to be a long-term solution but sometimes they can help ‘lift’ you to a point where you can start to see some light at the end of the tunnel.
I would also ask your GP about a Mental Health Care Plan (let the receptionist know you'd like to book in a longer appointment so you've got time to discuss this with your doctor). If you're not familiar with them, a Mental Health Care Plan will let you access a psychologist/clinical psychologist for 6 sessions (potentially more) to discuss your depression and panic attacks. These are medicare-rebated (you get $83.25 back for each appointment). Perhaps you could ask another parent or a neighbour to look after your 4 year old while you attend appointments or schedule them fortnightly for when your husband is back in town.
I work with people with depression and panic attacks and I know how debilitating they can be - add in your social isolation and I know you are suffering at the moment. There is a light. Please contact your GP and get some advice about how to work through this?
All the best.