First, congrats on your 43 pound loss! Second, I completely understand how you feel. I started going to the gym when I was at my heaviest weight. Here I was, huffing and puffing on the landing of the stairs (all the machines/weights/classes are on the second floor) and feeling completely like a fish out of water. Part of me wanted to bolt down the stairs, head to the parking lot, and write off my yearlong non-refundable membership as a "donation", and I would have, if not for my stubborn streak. Here's a few things that helped me out in the first days and weeks:
1. Wear headphones. The gym I go to has music piping through speakers overhead, but sometimes you want something with a bit more oomph to get you through a tough workout than the latest teen sensation crooning in your ears. Headphones also let you drown out conversations next to you, which in turn makes the crowd around you fade into the background.
2. Check what times you go to the gym. The 5 PM after work rush is when it's usually the busiest, so if crowds or equipment availability worry you, try to either go earlier or later. The weekends are also a good bet for fewer numbers, especially if you go right when the gym opens.
3. I've come to the realization that most people don't care what I do. Everyone is so caught up in their own workout that they hardly pay attention to anyone around them. Personally, I know that the only time I pay attention to the person next to me is when I get on/off my bike or when I'm loading up weights, just so I don't bump into anyone on accident.
4. Usually, if someone does
notice you, they're not thinking "OMG, look at that (insert insult of your choice here) over there. WTF." They're more than likely admiring that you're taking steps to improve your health and quietly cheering you on. I was biking away one say on the stationary bike when I felt someone touch my arm. There was this lady that wanted to let me know that she was using me as a pacer and that I was totally kicking her butt because she couldn't keep up with me. That was the shot in the arm that I needed to get me through my mileage, especially since I was already talking myself into quitting before my time was up.
There's an elderly man at my gym that does nothing but wander around and talk to people he knows, it seems. Every so often, he'll wave to the people running the indoor track and shout "You can do it! Keep it up!" so it's like the gym has its very own personal cheerleader.
5. Get to know the gym staff. They're more than likely going to be happy to help you figure out different settings or how to use the equipment. If your initial membership includes an orientation walk-through, use it to familiarize yourself with the things there, that way you don't feel even more nervous about not knowing what to do. (and it never hurts to ask if your gym provides this service. The worst thing they can tell you is no, right?) You could also luck out and they might have a complimentary "Fitness Perscription" where a trainer goes out and gives you a basic workout routine.
6. Having a workout buddy is fantastic. They really help on days that you don't feel like going, but know you should. I don't have one at my current gym, but my friend goes to a different gym on the same days I go to mine. We tattle on eachother on the days we miss and have an accountability system going on to keep us going.
7. Group classes are scary to jump into at first, but in the long run, they're incredibly fun. Check to see if your gym has beginners or 101 classes to get you started. They're a great way to meet some fantastic, supportive people and try out something that you've always wanted to do but were afraid to try in a safe setting.
8. TAKE BREAKS. Usually you can leave a towel on your machine to signify that it's still in use while you slip away to get some water. Or just stop what you're doing and sit for a bit. If people give you the stink-eye for taking up the machine, just let them know that you're in between sets but you'll be done in a while or that you have X amount of time left on your cardio machine. Keeping on going just because you think someone will look down on you for stopping will only lead to burn-out and potential injury.
And on that note, don't kill yourself doing weights or cardio either. Just because there's someone going light speed or lifting a ton of weights next to you doesn't mean that you have to do the same. Everyone starts somewhere and eventually builds their endurance and speed up to the point where if they want to go a billion miles an hour on the highest incline without breaking a sweat then they certainly can. Other people are celebrating the fact that they're not out of breath going 2.5 miles an hour on flat terrain and can lift 5 pound weights. Take things at YOUR pace and listen to what YOUR body tells you it can do for that day. There might be days where you kill it at the gym, where your muscle strength is awesome and you feel like you can take on the world. There will also be days where you really don't feel like even showing up, but a gentle, slow workout is better than no workout at all. Then there are days where you just have to take a break to recover.
And above all, have fun.