Your health should always be your number one priority. You can always do another start up. You can always earn more money. What you can't do is get back your time and your health back.

It is a very difficult thing to do but you need to look at yourself and honestly answer this question: If I don't put my health in the number one spot where will I be in a year? 2 years? 5 years? 10 years?

If this were a technical problem with your game you would search for a solution. Do the same for your health!

You did not say where you live other than it is winter so the southern hemisphere. I am going to guess an Asian or South American country from your comments about restricted health care and lack of safe place to exercise. Please correct if I am wrong.

You need to get this shit sorted though. Even if that means ditching your start up and getting a regular job. You said you had a higher paying job before your degree? Can you go back to that job or similar? Do you get any kind of private healthcare with such a job?

I know you are in a financially difficult position but every penny you put into anything but your health is almost certainly a penny wrongly spent at the moment. Yes you might get lucky and hit gold and have all the money you need to get better but you can't bet your health on a hail Mary like that. You said you are young? If so you have a lot of life left (if you sort your health out) to do a start-up. Maybe now is not the right time. A start up is killer even for someone in excellent health so doing one in poor health is almost a guarantee for disaster.

If I were in your position I would do the following

* Research everything you can about your specific thyroid problem. Get as much information as you can about it from your doctor and search the hell out of it. Treat it like a bug and research, research, research!

* Use your research to find the right drugs and then look at how to source them. There is loads of solid, medical advice on free resources online such as the NHS websites which you should be able to access without any problem. Getting the medicine may be the hardest part but thyroid medication should not be all that hard to get as it is not a controlled substance as far as I am aware (I could be wrong where you live obviously).

* Get your diet sorted. Have a consistent meal and exercise plan. Weight loss is more about diet than exercise so eat right. You said you can lose weight but put it back on quickly. That is normal! A solid, prolonged change to your diet will keep the weight coming off and staying off. I know the thyroid problem makes this harder but it has to be done.

* Find somewhere you can exercise. There will be somewhere unless you really do live in an awful place.

* Look online for cheap glasses or contact lenses. You can get very cheap glasses these days.

* How much will a dentist cost? Look at your finances and work out how long it will take you to safe for the treatment.

* Have you got family or friends who can help you? Maybe you could live with friends to reduce rent costs? Do some simple work freelance?

I hope that helps a bit. I really can't stress just how much your health is the most important thing though. Excuse my language but fuck your start up if you are not healthy. There is nothing to gain from having a successful start-up if you are in poor health and cannot enjoy the success. You need to have a seriously look at your priorities and if a start-up is the right thing for you right now.