if your an engineering student and have access to milling machines and lathes....make your own weights from scrap material
get one of them gym balls...theyre like $10 at the most, and you can do a but load of core exercises on them. do not get one of those naff abs trainers though. they suck.
one of my fav's with the gym ball is, putting my tiptoes on the ball, and then doing press ups, not only do you have to do press ups, you gotta balance.
sit ups, really important to not just go up n down, do side to side, left arm right knee , that kind of crap...... pulses (ie come up, hold it, pulse small movements 3-4 times), leg raises (bend you legs if you feel your back arching.... most important point! if your back is arching its doing you no good)
you dont even need heavy weights, for my circuits i use 25Kg on a light aluminium bar.... but its a lot of reps, sometimes up to 10 minutes... slow reps, fast reps, short/longer movements, holding postions. granted it wont do much for bulking up, but it does wonders for toning and core strength
what is it about having other people watch you exercise that gets your goat? ( i was gonna mention you go swimming, but obviously that might not be the best choice lol) is it just a fear of how people will percieve you?
EDIT: i see its because of your ableness.
dont worry about it, i go to the gym and yeah theres a lot of guys who could probably bench press me without blinking. i can only manage like the bar + 15kg, but i dont care..... i have the added benefit of getting my technique right. my dad is good friends of an ex proffessional body builder, he taught my dad a lot about correct weight lifting techniques and he inturn has taught me....
id rather lift a little correctly, than try to be Mr Macho and lift alot incorrectly like they do in the gym i go to.
some of the guys in my gym are hilarious, they come in and work only shoulders....they look totally deformed, one of these days somesones shoulders gonna pop out because he has so much muscle on the front and hardly any at the back, thats if he doesnt topple over first from being so top heavy...his legs are like straws.
everyones different... i may be out lifted in the gym, i maybe out run on the track, but ill whoop your ass in the pool
same with you, you go hiking, how many of the meat heads in the gym could keep up with you on a hike? anywhere you go no matter what you do .. there is alwasy someone who can do something bigger and better, but at the same time you have something that you can do better than them.