You can talk to the career office, but my guess is that your GPA is good enough to get a job in engineering. At which point if you work hard, make yourself useful, get things done, get along well with others, and maybe change jobs a few times, you will have a fine career (if academics is not your thing, maybe stick to more hands-on or project management like work and let the more academically inclined do work like technical design).
The military does hire a good number of engineers for all kind of support roles and also for officer training. You can check GPA requirements on line somewhere and talk to your ROTC office on campus too.
Also, if you can work through the material but just can’t handle the workload, you consider dropping down to 12 credits or even part-time and working … and keep on chipping away at those degree requirements. One difficult course or two during a semester may be more doable and less stressful.
Relax, not every engineer has a 3.5, actually very few really do.
Ignore being 24, just keep your living expenses low and keep on working towards your goals. If you graduate by 27, you can still enjoy 40 years as an engineer before you hit the social security retirement age.
Do you like petro engineering or is this part of the issue ? The air force and petro seem odd to me, but what do I know … Maybe an ME degree or ChE would be more flexible, allowing you to work say on planes as an ME, which maybe would add a spark and some real interest to your studies …
4 year engineering graduates are not typical … so don’t sweat it. But have a plan and work towards it.
12 credits a semester for 2 more years or less if you go during summer would get you your degree.
Any engineering degree is pretty transferable to most engineering jobs and should get you a salary above $50K to start. Again … just work hard and you will get far in life.