When I was 15/16 I really enjoyed contact sports (Rugby, Boxing mainly) and weight lifting (I'm male). Was quite muscular, in fact very muscular and strong for my age, probably since (genetically maybe) I have always been able to put muscle on easily. I honestly don't know and can't remember how big I was. For some reason, started to become more paranoid and self conscious onto how I looked and eventually I lost confidence rapidly. I began to shed muscle and in general lost weight, by simply running marathon style for ages and not doing any high intensity workouts for about 3 years. I'm now about 36 inch chest, 28 inch waist, and 10.9 stone (and 5 foot 11, but height increase might make the effects looks larger). I was much less bulkier (Much much less) and I feel better in how I look and definitely more confident. But family are telling me that I'm wasting, and that I don't eat right, which I do, just not as much as I used to in order to have the energy for the high intensity workouts that I did. I get comments from my friends and girlfriend all the time about it now. I know its a problem, but I don't seem to want to do anything about it. I'm not particularly bothered about it, since I enjoy my 45 minute runs 3/4 times a week, but I just don't want to upset my family and other loved ones, since they're worried for me. Is there anyway I can tone up without having to increase in size? I'm not bothered if there isn't, I think I just need a bit of my strength back without risking what my willpower has worked for.
Has your weight changed rapidly recently to prompt the concern? You sound on the slim side but that isnt always a bad thing if you are comfortable. No idea what tone up without increasing size means, you are composed of muscle and bodyfat, either of which can be increased or decreased. Why not start some weightlifting again, if just to revive a hobby you previouslyt enjoyed?