I have regularly carried 35%+ of my body weight (in those cases more than half of it would be food and water) and still enjoyed it immensely. Actually, these were always the best walks because it meant I was going somewhere remote and adventurous.
3kg for a tent is very heavy by today's standard (unless it is a real mountaineering tent, able to withstand strong winds and snow loading). The two tents that I'm using are 1.2kg and 1.7kg, depending on where I go. They have been in pretty rough weather but wouldn't survive gale-force winds.
If you don't want to spend more money, well, does the ~1.5kg you could possibly save on a tent really make that much difference? I personally don't think so. It is all in your head. In my opinion, there is way to much emphasis on pack weight in outdoor discussions. Of course low weight is nicer, so you should make some effort to keep weight down. But there are other things that are more important for how much you are going to enjoy your adventure.