Wheelchairs and hospitals

For the last 4 or 5 months, I've been thinking about hiring a wheelchair from the Red Cross. I think it would help me be able to go out more and enjoy life. Hopefully it would make me more independent! 
At the moment, the only time I go out the house, is to the doctors! About 3 weeks ago I tried to go to Asda but only managed to be in there 20-30 minutes before I had to go and sit down in the car. 
My legs have been bad for about a year now. The first time I had any problems with them, was April 2011. I woke up one morning and I couldn't feel them at all. I struggled out of bed, got dressed and went to school. It was really hard to walk. If you imagine, not knowing whether your feet are on the floor or not because you can't feel them! I was in a wheelchair all day at school and I still couldn't feel them when I got home. I ate my dinner and dad decided to ring the NHS helpline. I spoke to a really nice nurse who asked me lots of questions. At the end of the phone call, she suggested I go to A&E. 
We arrived at A&E about 9pm, me and my dad. I had a blood test (I nearly passed out and I had a panic attack) and the nurse checked me over, about midnight.
They couldn't find anything wrong.
So we waited another 2 hours in A&E and then they send me along to the childrens ward. Another doctor checked me over but still couldn't find anything wrong. They said they wanted me to stay the night but I had a panic attack and said that I wanted to go home. They agreed and said that I should go home, get some sleep and come back at 8 the next morning.
The next morning, I came back and they did loads of tests on me again. Still nothing wrong. 
At 11am, my dad went to the hospital shop to get me something to eat and some magazines. I feel asleep and when I woke up I was really confused. Where was I? Where was this strange place? Why was i on my own here? 
I had another panic attack and I can't really remember much but a nurse had to give me an oxygen mask thing to put over my face. Dad came back and mum came to visit me. Another doctor came to check me over. Still nothing wrong. They sent me home.
Since then, I have been getting severe pain in my legs, as well as numbness and other symptoms. I can't walk too far and I think a wheelchair would improve my quality of life. I get really upset and frustrated that I can't go out and do things.
I have spoken to mum about hiring a wheelchair and at first, she wasn't too keen and explained all of the negatives to me, but I am sure about this. I have thought long and hard about the positives and the negatives. 
I am a bit worried that people will stare and ask questions but I guess I'll just have to deal with that when it comes to it. 
I would only use this wheelchair when I go out, once a week or so. I won't use it round the house because I want to use my legs as much as I can. 
I haven't spoken to dad about this yet but hopefully he will see how this can help me.