College Major Decision.?

Currently I am closing my second year in College, but to be honest I'm not proud. I feel ashamed, depressed, lonely, and that I've lost my purpose. I'm not sure what to make of what I'm feeling, but everything I do seems worthless. I think it is best to start with what amounts to my time in the Engineering department. I came in a Chemical Engineering major. I had all the intent and vigor to do so. I feel like I should accomplish something with the time I am given in college. In all reality I should have been weeded out the first term I was ever in Chem E, but I persevered, and made it through. Yeah I was behind in math, but I thought that it would work itself out for the better. Eventually, my second year came, and I came back with a plan. I had to make sacrifices, and I did make them, however it wasn't enough. I got slaughtered. It wasn't because that I partied, got too lazy, didn't keep my eyes on the prize, didn't do my homework, or see my professors, quite the contrary (though my math and physics teachers were quite unhelpful, and rude for that matter) Personally I know that I got screwed over I don't care what anyone says I cannot be swayed from this fact. So I changed my major to undecided, and did a bit of exploration, took a few psychology tests that told me I was basically better off being a truck driver, or a maintenance man, and Changed my major to Biology, but the thing is, I was never really happy changing my major to Biology. It really eats away at me I don't know why. Everything seems so empty, so unclear now. I feel so lazy I have time now, and all I do are bacc core cles. The only cl of substance that I am taking is Integral calculus. I just don't know what to do anymore. I worked my *** of to get weeded out, and listen to all my friends say how great everything is going for them. I ******* hate the position that I am in. I have no clarity of where to go, I feel like I am wasting my parents money, and I feel pissed off because I was weeded out because I had some bad professors. However there are times where I think it is possible to go back into Engineering. how if I just tried again things might be better, how If I take summer courses my "time off" won't totally knock me off balance. But there is always that thought that I may be bullshitting myself. How do I know that I won't end up just like how I did the beginning of this year? why am I thinking this way? I've had some great teachers that made me feel empowered. I had a great Organic Chemistry Professor, and the math teacher I have now is great. When I left Engineering I had lost all tastes of learning, but when I took the second cl for the Organic Chemistry series, I felt great. in fact well after the exam, into spring break I still kept writing reactions up on a whiteboard. and now this term, with my new math professor, I like doing math. I love rewriting my notes, and doing the homework, and rewriting the homework. I love learning about integral calculus. I just keep thinking to myself is it still possible. I gave up so much first term and got so little. I am a Bodybuilder, and I sacrificed that to try to do well in school. I guess in short, what am I feeling? and is it right for me to go back into engineering ?