Stay in touch with people related to your core field
If, due to financial pressure and other problems, you were forced to take up a Mcjob, you can still do much to keep out of trouble and make ends meet. Stay in touch with the people belonging to your core industry - no matter what is is - as it will help you find opportunities that may come from time to time.
Staying unemployed is worse than making little money. The Mcjob may not be able to give the respect you deserve, but getting some income is better than sitting idle for months. Talk to friends and relatives from time and time and ask them about job opportunities.
Identify the problems that caused you to take up the job
Since you are misfit in the Mcjob as you deserve better than this, you have to identify what caused you to take up the low paying work. You may be skillful, but if the economic crunch is behind your misery, you have to bear with the job for a few weeks, or even months.
Continue your education
If you are not educated and had to take up the Mcjob due to little expertise in your core field, you should continue learning. Enroll in part-time courses and try to get experience by working in shifts. Mcjobs are usually flexible in the sense that they are part-time, allowing you to get plenty of extra time. Do not stop learning, because if you do so, you will remain at the Mcjob for a long time.
Be happy and move on
Regretting your job will not work. Be happy and confident, you will soon find an opportunity that meets your education, worth and ability. Working at a low paying job may not give you satisfaction you need, but you will surely learn to work in difficult conditions.