Fired from job because previous employee came back

A little overview; I was working at a family owned dental clinic as front desk for about 3 years. My mother also used to work there. The owner of another clinic approached my mother and asked her to leave her old job and join here full time. She refused but referred me. The employer offered better pay so I joined her clinic. Worked there for 2 months, everything was running smooth. Then last week, her old guy who assisted her and did front desk work as well came back, and I was fired on the same day. Performance issues were cited but I was never made aware of any issues or put on an improvement plan. Also, upon joining, I was not presented any contracts to sign. I am now out of a job and can not return to my old employer. Someone please help me understand my position and what I’m entitled to? Thanks