Hello Nicola,
Sorry to hear of the issues you have had to deal with in managing your t1d.
What type of support do you get with your t1d management, so are you under the care of a specialist Diabetes team ? Have you ever completed any course for t1d such as Dose Adjustment for Normal Eating ? Have you ever been given the option to try a pump or indeed change insulins ?
It's hard for me to establish why you feel unwell but what makes me feel unwell with my t1d is running erratic levels, so playing the high/low game each day, lack of sleep through running high during the night then waking feeling groggy and unwell, or going low which can knock me for 7. I try to keep my levels as stable as possible to combat the high/low game and if running high/low I just take it very easy that day. To achieve good stability I eat low carb foods and use a pump which micro manages my levels to keep me in range, I use exercise as a tool too for helping me feel better, it releases serotonin which gives me a boost as well as helping me achieve more stable levels depending on the exercise I do. I try to avoid high carb foods as much as I can, although I don't deny the odd treat I will try to manage it as best as I can with insulin control. Each day is a challenge but if I can start the day with a low carb breakfast and stay below 10 mmol/l it sets me up for the day and I feel I have a head start on my t1d by doing this.
I think if we let it get to us then mentally it can be a strain too which impacts on how we feel, so playing sport or having a passion for something like art/music can take our mind of it, it's important to have past times that can take the mind off t1d too.
Let us know more about yourself and what your current regime is like, perhaps we can help shed some light and support you better ?