First of all, try and avoid these ambulance chasers if at all possible. They are not doing it because they care about you.
Have you got legal expenses on your motor insurance? If so, they will put you in touch with a solicitor and things will be done properly.
Check your house insurance too - some policies allow this sort of claim.
But you have plenty of time to find a solicitor. The immediate thing to do is make a comprehensive record of the accident itself and the immediate effects to yourself.
Then keep a diary of all appointments, symptoms, pain and discomfort, no matter how slight it seems at the time.
Disturbed sleep, nervy, depression....? Write everything down.
Time off work, travel costs to appointments, prescription costs ...every little thing. Keep receipts.
Keep copies of all correspondence.
Sorry if this all seems overwhelming. It is necessary and could save you many many hours in future.
Good luck with it all, and I hope you have a quick recovery.