I'm due back at the doctor next month for more bloodwork and a check-up, but at my 3 months on T visit, my blood pressure was lower than pre-T (probably because I was less stressed, unfamiliar medical situations/facilities freak me out), and my cholesterol hadn't changed from being what my doctor described as 'perfect'. I'm also in very good shape, workout 5+ days a week, and eat a very healthy diet low in dairy and no red meat.
T is a risk factor for a lot of conditions and diseases, no doubt. I was discussing this with another transguy from my local trans community group last week. He says he's done a lot of research and has read many articles from medical journals and other sources that contend that there's no evidence that taking testosterone increases the chance of diabetes in FTM's who were not already in a high risk category, such as being significantly overweight, living a sedentary lifestyle, poor diet choices, and high blood pressure and cholesterol.
T is only one risk factor though. As others have said, healthy eating habits and exercise are crucial to maintaining good cardiovascular health. Some people get dealt some really bad genetic cards, it's true. It is really unfair, but it may come down to stopping HRT or making some major lifestyle changes.
Nygeel, I'd definitely make sure your dose isn't too high first of all, too high of a testosterone level could definitely cause more of the elevated levels you described in that relatively short time period. You're smart to seek help with the pre-diabetes symptoms you mentioned too. Hopefully they ordered some glucose tests, that's nothing to play around with. I'm sorry you're having such a rough time on T. For what it's worth, I think it's very responsible and mature of you to consider the possibility of having to go off hormones for the safety of your health, although, hopefully your doctor will be able to offer some insight into the numbers and your symptoms and come up with a plan to improve them without ceasing HRT altogether. Another thing to think about, even if you had to stop for the time being, it's totally possible that if you later had a hysterectomy maybe you'd be able to resume T since you'd need about half the dose to produce the same changes/effects.