You should obtain a copy of your credit report to find out how horrible it is and what you are able to do to improve your credit and credit scores.
If you have a crappy job, it might be to your benefit to find another job, or get the skills to be able to present better skills to another employer.
It goes to say, you must immediately start a saving account, even with the crappy job your currently have. You have no financial plan in the event you are laid off from your job or take care of any emergency that might arise.
You might also want to contact a local mortgage lender and obtain literature on the requirements of being approved for a mortgage loan and the process.
You might go online and obtain some information, however, there is nothing like a face to face contact with a mortgage lender, that would be able to explain the various mortgage loans available for you to apply for.
I hope this has been of some benefit to you, good luck.