I feel your pain.
Great advice from the other people on this forum.
Identify where your initial business came from - is it possible that initially, friends and family also helped spread the word for you to their friends and colleagues, and this is where the boost came from?
Marketing is a funny thing (Not as in haha when you need, but don't get results). One phrase that sticks with me throughout all of my businesses is: "If you do what you've done, you'll get what you've got".
I'm a firm believer that you should never give up - and that in mind - you have the ability to turn this around.
Check your marketing material, and stick it everywhere. I'd suggest estate and letting agents, especially around areas where Uni's are. You're likely to have a slight influx when students move out.
Try and partner your business with domestic cleaning businesses, home help etc.
Incentivise them to generate you business by paying commission (Say 10%).
If you're doing nothing, go door to door in affluent places. Knock the door, and say:
"Hi, sorry to bother you, I was wondering if I could just give you this leaflet on XYZ"
You will get a better response from this than just popping the leaflet through the door.
Think about B2B if you can - perhaps you can also target restaurants. Don't forget the Environmental Health people can cause havoc if grills and ovens are dirty - you could be the solution to all their problems.
Geography may be playing a part - go further afield if required. Spread your wings a little.
Best of Luck! It's tough out there - but it's worthwhile!