I tried riding a road bike and found it very difficult. I'm too used to my mountain bike. When I tried to brake, I couldn't stop, and ran into the kerb 
Maybe the bike is the wrong size for me I don't know, it's my partners old one (we're the same height) I'd really like a hybrid bike (that is the correct size) but I don't have any spare money
I've agreed to do a sponsored bike ride with work in a couple of months (100 miles over 2 days, lots of hills) and I may end up doing it on my hardtail which I ride to work on, but I know its not ideal, but I'd rather be comfortable and have confidence in my bike.

Maybe the bike is the wrong size for me I don't know, it's my partners old one (we're the same height) I'd really like a hybrid bike (that is the correct size) but I don't have any spare money

I've agreed to do a sponsored bike ride with work in a couple of months (100 miles over 2 days, lots of hills) and I may end up doing it on my hardtail which I ride to work on, but I know its not ideal, but I'd rather be comfortable and have confidence in my bike.