Is my suspention to low?

My car seems to be a lot lower recently. Everytime I go over a bump or a dip in the road it scrapes on the plastic covering under the car at the front, also when I got the car i could walk under the tailgate now i can't as it seems lower and bash my head everytime. I had large tyres on at first now i have had to change them for 185/14 they were 215/65/16 are these to big. They rubbed on the front shocks everytime i went over a bump or a dip in the road the car bounced up and on the suspention arms and actualy wore the tyre down about 2in on the inside. Could you let me know if I need to change the front suspention legs as well as the back shocks,or can the car be raised. I thought i would ask before going to a garage, as they rub their hands together when they see one these cars coming in. many thanks
look forward to a reply
Brian