What can I do to prevent being chaptered out for not being able to pass the APFT?

The Air in Germany is the exact same as the US. Unless you are stationed in the Alps above 5000 feet, it should not be a factor. Even then, the Army answer is to acclimatize, drink water, and do more PT. The Army only plays away games, so get used to other places. It sounds that your medical condition is the primary reason for the chapter. Follow MSG (Join to see) advice. Understand what the chapter is, then use TDS. I would have to imagine continued or further diagnosed syncope is disqualifying. AR40-501, pay attention to what entry standards are and what retention standards are. Different chapters in the reg.

What is your medical provider telling you? If they put you on a hyper-restrictive profile, that could contribute to the chapter. Especially if it makes you non-deployable. I sympathize with your weight gain, but the Army has the compassion of an inert lump of steel. They'll give you specified time periods to get into compliance, but then you are on your own. AR600-9. A handful of medical conditions will get you a mulligan on AR600-9, do not put any eggs in this basket. They are restrictively applied and very narrow.

If you manage to avert this chapter, you need to really get in touch with your inner athlete and get in shape. It's easier to get in shape if you had ever been in shape. AR 350-1 governs APFTs. TC 3-22.20 is the Manual for Physical Readiness Training. Hell you can even down load PRT apps to your phone. You'll need to see what combination of nutrition, strength training, cardiovascular training, and functional fitness works for you. You have to be in your 20s? If you are physically (high intensity) active for more than 60-90 minutes per day, 6 days a week, and weight is not coming off, you need to take a hard look at what is going into your air intake valve in the way of food and drinks. Cut soda. Cut any sugar beyond what is in foods. Reduce unhealthy fats, particularly fast food. Pomme Frits? Wave good bye. Good rule of thumb: equal parts protein, cleaner carbs, and veggies for meals each portion slightly smaller than the size of your fist. There is conflicting medical advice for whether 5-6 small meals are better than 3 solid meals, particularly for endocrine health. I used a book called Body For Life. The eating and fitness plan worked for me until the last couple years on active duty, then I had to do more PT and eat even less. You are going to have to reckon with this as the new ACFT is just months away at is point. If you fail that, you'll likely be flagged, barred, chaptered, and handed your 214 and a strip map to the front gate.

You said your NCOs were not going to help you and you don't know where to start? I find that hard to believe unless they know the train is already rolling on the chapter. Regardless, if you haven't been counseled by the Commander or his designate on which chapter etc, it isn't a done deal. If you haven't been counseled, you need to take initiative and seek out the unit master fitness trainer and the nutritionist. The MTF or wellness center usually has a weekly or monthly nutrition class. Should be two mouse clicks away from a search engine.

If you are chaptered for this medical condition, I'd reasonably anticipate that your RE Code will at least be 3 if not 4 and reentry in any armed forces branch will be a highly unrealistic prospect.

I'd also start getting my affairs in order, especially financial with a goal of 3-6 months salary. Start saving if you haven't already. Consider what life after the Army will look like.

Based on what you said, I would gather that you are to receive a Chapter for medical reason. But, regardless of what the reason is, you will have the opportunity to challenge this. You are to be read (counseling form) what the Chapter is for and why. You are to be notified of all of your rights and responsibilities. You are to be provided an opportunity to seek legal assistance. But yes, you are correct that you have to fail two consecutive record APFTs to receive an APFT chapter.

As SSG (Join to see) gave you the regulations to research, read them to fully understand what is going on. I can tell you that if the packet submitted by the Commander is not completed to the letter based off of the checklists they need to follow, the packet will be rejected and the Command will have to start back over.

Having someone on a team that might pass out if their blood flow increases could put everyone in danger. Do you expect them to accept that risk? Would you? What if you passed out during a live fire exercise or an actual engagement with enemy forces?
With that said, you need to find out if you will be processed out for APFT failure or due to your medical condition. If your syncope prevents you from being able to PT, you might be a candidate for medical separation. Talk to your Doctor. See if they are recommending medical separation.
Either way, make sure you have everything pertaining to your medical condition documented. Make copies of everything and get in contact with a DAV rep to help you apply for VA disability once you get out. Start preparing now and things will go smoother.
Good luck. Try not to "end up getting pregnant" again unless you want to add another set of problems.