My responses to your questions:
1. I don't come from a prestige college.
It does not matter. What matters is what you offer to the schools, including your GMAT/GRE score, your work experience (quality and tenure) with achievements, your pragmatic career plans, your reasons for pursuing an MBA, your reco letters, etc etc.
2. Is there any hope for me?
Hope is never a good strategy; action is. See above.
3. Should I start preparing for GMAT?
No one else can answer this for you.
4. Will the loan be enough to cover education abroad, or do I need a minimum balance to pursue my education?
Too premature a question. There is no information about which country you wish to study, what format (1Y vs 2Y), etc. etc.
5. Are the global options doomed after Trump's visa scene?
No. Presidents come, presidents go. Your career will continue for over the next 20/30/40/50 years (depending on your age today). Will you define this future based on what's happening today in one country?