Can my Med Pay insurer subrogate on a settlement?

I was rear-ended a little over a year ago and am just now in negotiations to settle with the at-fault party's insurance company. The settlement documents state "bodily injury claim." My health insurance company filed a subrogation claim with the at-fault party's insurance company and so they will send them a check directly out of my settlement and then send me a check for the remaining balance. Out of that balance, I am responsible for paying my chiropractor bills. The remainder is then mine to reimburse for time/travel to and from dr. appts, on-going and future medical costs, etc.

I'm wondering though, since I used my own insurance's med pay to pay some of the chiropractor bills, can my insurance company subrogate me for the amount they paid to the chiropractor? Will I have to reimburse my insurance company out of my settlement money? The at-fault party already reimbursed my insurance company for the costs associated with repairing my car so that's taken care of.

I'm in California.

Thanks!