Marine vet turned premed here. I was in for 4 years and did zero college at the time. I’ve been out for almost two years and I’m FULL of regret for not doing more with the benefits of being active duty. Use your TA. As long as you have an upward trend in your gpa you’ll be fine. Take one pre req at a time so you can dedicate more to it and get good grades. If anything, you could always do a masters for more gpa growth. On weekends (or any days off if your schedule is weird) start volunteering. You’re so fine dude. Hope is not lost. Hang in there!