G'day new here need help gearbox probs

[Damnit]

G'day, one an all, I hope you guys are well, i'm from queensland in australia and I own a 98 prado 3.4 litre v6 petrol 5 speed manual. When I bought it I also bought a mech manual so that I could learn how to look after my baby and fix it myself, especially if I was all alone in the middle of the bush. But, I've now come across a problem that the manual of my mates can't work out, I''ve been having trouble with the gears, when I change from first to sencond it stops just before going into second as if there's something stopping it. I use some pressure and move it from side to side and it goes in as if it's pushed past something, it does it when changing feom 3 to 4 but not as much and from 2 to 3 but not as much and when I put it into reverse but if I double clutch reverse it goes in much easier. It started to happen with reverse first then second then 4th then 3rd and it's slowly getting worse. I changed the clutch about 6months ago and everything was sweet ( real nice and very smooth gear changes) until about a month ago when it started to happen. I noticed an oil leak in the transfer lever housing seal which I fixed and then changed the oil ( there was not enough oil missing to have caused any damage). It has me stumped aswell as everyone I talk to about. Please help before my baby dies