Hello! New guy working at it.

I was an adult-onset swimmer and really struggled my first couple of months (years??) with swimming.  It'll come back to you - and don't worry about being self-concious, we're all built how we're built and just putting the effort in means a lot.  Each time in the pool just try to do a little more than you did before, and you're actually better off swimming shorter intervals anyway until you get the feel and some endurance in the pool.  Good luck!!

Welcome to BT and the multisport community. 

Obviously, be careful with your foot.  We had a guy in the local club (this was a while back, when I was in Illinois) who also had a foot problem so he WALKED the "run" including a sub-14 hour Ironman.  He'd don a cat-in-the-hat outfit (hat, white gloves, tail) and his hiking boots, so don't rule out doing all 3 just yet. 

If you swam on a team as a kid, you certainly can understand that technique is important for swimming. 

Are you swimming in jammers or trunks?  My guess is trunks which function as a drag suit.  Get yourself a pair of jammers (cheap lycra for now, since losing 60# will drop you several sizes).  As you get closer to some "final form" you should switch to more durable polyester jammers. 

Take your time.  I tell people starting out in the pool to swim like you're taking a "walk in the park."  Too often, because of fear, anxiety, etc. they'll get in the water and then swim like mad to get to the other end of the pool which is like trying to run a 100-yard sprint.  They're tense and holding their breath (which adds to the tension) and don't understand how lifting the head rather than rotating causes the legs to drop...like a rock...They're breathing is the "blast and gasp" method where they hold their breath, blast it out all at once, and then gasp for another breath. 

S-l-o-w d-o-w-n.  Go really easy, taking your time on the arm strokes.  Rotate to get a breath and then exhale (I suggest humming which helps keep water out of your nose too) while your face is in the water. 

Easy to say "don't worry about your weight".  Not sure where you are, but I recommend you volunteer for a nearby sprint-tri.  You'll typically see that competitors have every body style imaginable and are generally focused on their own race and not how anyone else looks (at least that's how it was when I started in 2005).  Some will look fast.  Some won't look fast but will be fast.  There will be a few very high-strung participants, but most of them are probably smiling and enjoying the day.