Thanks everyone. I rode again yesterday and I realised that it is way too big. My seat post was too low before so I didn't know how big it was for me until I put the seat post in the right position. I've got to get a new bike!
Tubeless sounds good. I would like to get a more nimble bike so it's not so hard to climb hills with. Or at least an ebike, since I take this bike around town as well and I want to get around faster.