This is a bit of a long post but I truly need advice.

Okay so in Secondary School I did okay at my GCSEs. I always wanted to become a doctor. However I had an unpredictable personality and that led me to do somethings outside of school which got me into trouble and therefore I couldn't pursue medicine, I settled for IT instead. After I left school I started working as an IT Support Agent. That's been my job ever since August when I quit work but I didn't like it anymore and thought I could find something better and not in IT (I regressed in my progress in IT). 

Now I've been jobless I decided I wanted to pursue my interests in medicine again. I can do a foundation year in September and then apply for University in 2022. I'm 21 years old.

 However, my dad tells me it's too late and I should look at making something of my life now get a women (I also have savings up to 50k), he also thinks that it's unrealistic for me to do medicine because I have random spikes of energy rather then a constant flow of energy meaning he doubts whether I'll succeed in my studies.

I'm looking for advice, should I just leave the doctor field for those are actual made for and just start looking for a job instead?