I was a mechanical engineering major and I regret not taking more computer classes in college. Think of this as a time to learn and experiment. There is a good chance you will appreciate more breadth in a few years. Even smart college students don't always know what they will really end up doing in life.
Another option at a bigger school is to look into undergraduate research work in one of the labs on campus. We regularly host engineering or physics students and they tend to enjoy it, get some valuable experience, get paid, and earn a good recommendation for their next phase in life.
There is also nothing wrong with working on side projects. Just spend a little time thinking about how you can use them as a piece of your resume when you graduate.
[1] my sister had similar problems feeling unmotivated in college, and I found out she was on this schedule. Adding other classes helped a lot in her case.
Don't forget to socialize, while you focus on that your mind will do its thing without you even realizing.
Music helps some people.
Force yourself to stay disciplined, habits take a while to form. You can have a friend help. Friends are good at telling you when you're being dumb/lazy/distracted.
Your college might have a workshop to help you with vital skills. Take advantage of it. When I did my grades went from Bs & Cs to As.
Work in 25 minute blocks with a 5 minute break. Studies suggest this is an effective time split.
Also, one key: Do the difficult stuff you're dreading first. Always. A lot of famous successful people point to this habit as the main reason for their success.
Just get the ball rolling!
The goal is to avoid distraction and put systems in place to avoid them. I was a classical studies major so disconnecting from distractions was pretty easy, but if you have to do work on your computer you should consider other systems to avoid distraction.
