@ehuntington I love that you have reached out, it shows initiative which means you are serious about this which is a really good place to start from! I love too that you called yourself out on how you got where you are, you called yourself "lazy", well, now-you're going to be un-lazy. You are obviously tired of being overweight, unhealthy so let that drive you! Ok, now where to start.
Get up in the morning with enough time to go walk for 15 minutes (or for as long as you can) with NO stopping, just walk with intention, set a timer on your watch, then put it on no notifications so you can't be bothered by anyone and try to give yourself 15 minutes to focus on your health.
You will do this after dinner as well. Just 15 minutes of walking.
That is what you do the first week. Start today, Monday, end Friday.
Saturday and Sunday (presumably you're off from work) Same thing as above but add a midday 15 minutes.
This will help you jump start your metabolism, it will wake up your body and it will be ready for more exercise, it may also help decrease your appetite
The next Monday-Friday you will do your 15 of straight walking, then you will go to the gym and you can get on a treadmill and just walk, try to do 30 minutes. That's all, just do the treadmill for 30 minutes, slow but steady. This will give you a chance to get your bearings, the gym IS overwhelming! But because you are there doing familiar to-you-things, you will start to gain confidence in being in that space. Do NOT worry about other people, in fact, smile at them, say Hi to at least one person because you know what? They are the same as you, they are there to improve their health just like you. Once you're on the treadmill and you're in the groove, look around at the equipment, learn where things are so when you go to add on to your routine you know where to go in the gym.
You have weekends off but stay active, park farther away from stores, take your dog for a casual walk, clean the garage-stay active!
You do this routine for 2 weeks.
Week 3 you re going to do your 15 minutes of walking at home then it the gym for a circuit on Tuesdays and Fridays, almost every gym has an area where there are a bunch of machines in a row or circle that will give you a full body workout. You are going to do a full circuit, light weights, the idea is that you wake up those muscles before really taxing them by lifting heavy. You go LIGHT, only do the circuit once. Also, HOW to do each machine will be ON the machine, look for a badge/lable that explains how each machine works and follow those directions, if you have questions go get staff, people love to help other people, let them.
Week 4, do the 15 of walking and rejoice at how it is getting easier! Add another day to your circuit training, Maybe Mon-Wed-Sat
Week 5 add another ROUND to your circuit, you are now doing this routine 2 times while you are at the gym.
Week 6 add another round to your circuit for a total of 3 PLUS your walking 15 minutes in the morning.
At this point you can create a plan/workout for yourself or maybe you'd like to hire a trainer, the main thing here is the you went from being, "I don't know where to start" to having routine that gave you the ability to go on and do more, you started your journey and you're feeling so much better physically AND mentally (I promise you will)..
You got this OP, I cant wait for your future post about how great you are doing.
For how to eat talk to your Dr. you said your diabetic so that's got to be managed also, they might have you do your TDEE (there are loads of calculators out there but talk to your Dr. about your nutrition)
If you're cleared by your Dr. to work out: check out
https://www.muscleandstrength.com/workout-routines they have loads of workouts!
STAY POSITIVE, you deserve to feel good!