If your spouse was a US citizen, then yes, it would be easier in that you would not have to wait for a visa to become available, whereas if you marry a lawful permanent resident, you would fall into preference category #2 and would have to wait. So far, you did everything correct. You need to wait until a visa is available (times can vary) and once one is available, you can submit the I-485 to adjust your status. You are technically legal here while your case is pending.
Since you overstayed, you should not leave the country (even with authorization to do so) because you could and probably will run into problems (be denied entry) when you try to re-enter the borders. If you can, stay inside the country until you adjust your status.
Try calling the service center to check the status of your application, or do it online if you have an A number assigned to you.
Obviously, if you do anything stupid, you will give them a reason to deny your application, so the key here is to stay put and keep your nose clean.