Hi all, I'm fairly new to cycling. I'm a 26 year old female and I have some old mountain bike (lol) that I bought for £50 in 2000. 
I've recently starting cycling again and have a bit of a personal issue I was hoping someone could help with! I'm OK doing short, flat distances, but anything longer or anything bumpy I end up with the female version of numbnuts, and truth be told it's scary and I'm not sure how to sort it! It doesn't go straight away either and after my longest ride (17 miles) it took 2-3 days to feel normal again.
I never fitted my bike or anything and I'm not sure how to. I currently have a wide, gel padded seat which is comfy but not sure it's doing me any favours. I have a 21" frame (am 5' 11" with 32" inside leg) and when on the saddle my legs are nearly straight but not quite while my foot is on the pedal at it's lowest point. The only other issue I have is that my handlebars seem fairly low and I have to lean forward to reach them but they are at their highest.
So (to sum up my epic first post
):
1) Do I NEED to get a new bike?
2) Has anyone else ever experienced numbness in their nether regions before (particularly interested if female)?
3) Should I whisk myself off to a medical professional?
Generally any words of advice would be much appreciated.
Thanks in advance!
Novice
P.S Really don't want to stop cycling though I'm loathe to go out until my little problem is sorted. This last year has been some journey involving losing 4 stone, still have a bit left to go and now I've found something I enjoy I want to be able to do it more often!!

I've recently starting cycling again and have a bit of a personal issue I was hoping someone could help with! I'm OK doing short, flat distances, but anything longer or anything bumpy I end up with the female version of numbnuts, and truth be told it's scary and I'm not sure how to sort it! It doesn't go straight away either and after my longest ride (17 miles) it took 2-3 days to feel normal again.
I never fitted my bike or anything and I'm not sure how to. I currently have a wide, gel padded seat which is comfy but not sure it's doing me any favours. I have a 21" frame (am 5' 11" with 32" inside leg) and when on the saddle my legs are nearly straight but not quite while my foot is on the pedal at it's lowest point. The only other issue I have is that my handlebars seem fairly low and I have to lean forward to reach them but they are at their highest.
So (to sum up my epic first post

1) Do I NEED to get a new bike?
2) Has anyone else ever experienced numbness in their nether regions before (particularly interested if female)?
3) Should I whisk myself off to a medical professional?

Generally any words of advice would be much appreciated.
Thanks in advance!
Novice
P.S Really don't want to stop cycling though I'm loathe to go out until my little problem is sorted. This last year has been some journey involving losing 4 stone, still have a bit left to go and now I've found something I enjoy I want to be able to do it more often!!