Weak or just normal

Take it easy on yourself......   Baby steps, one day at a time, and you'll build up your stamina and strength. And do make sure everything is in check (e.g. thyroid, etc.) with a physician if you continue to feel low energy. You are in the majority, by the way . 

I don't know many people who can run 10 mins straight when they don't do it regularly!  So you are in better shape than you give yourself credit for.  I think that it is important to exercise daily - at least 30-60 mins but that can be a 10 min walk in the am and a yoga class in the afternoon or 15 mins on exercise bike and 15 min walk on treadmill.  AFter you do that for a week or two, start increasing the time and intensity.

If you are interested in running - google "couch to 5k" which is a walk run program that starts at 60 second run - 60 second walk and repeat.  You are probably able to start well beyond that!

Congrats on getting back on the exercise routine. Do not get dismayed. It takes time to build up to where you want to be.

you will get there!

What someone else does is totally irrelvant to me.  I swore to myself when I got out of the Army MANY years ago that I would never run again, unless my life (or someone else's) depended on it - and I haven't.  That said - I do ride my horses and my bike often and I do push myself on both.  I basically do not hike either but do walk to the park with my Corgi, walk to get to fishing spots and anywhere that need to or makes sense to me to do (I do the 10K Volks Marche up to the arm of the Crazy Horse Memorial.).  I go to the gym several times a week (especially during the winter as it's too cold and nasty to get outside and do much).  

Being addicted to running does not necessarily make someone else live longer - it just gives them a 'high' and make them think they are better than those who do not share their addiction.  Is it good to be as fit as you can be - yes.   We are all different with different talents and abilities - work to what YOU can - do not JUDGE yourself against anyone else! 

Just start out slow and listen to your body.  I am grateful that my hospital has a cancer survivor program which included a free one month membership to their gym that included a trainer that routinely works with cancer survivors.  After 4 1/2 months of chemo, surgery, and 7 weeks of radiation I could not do as much as you.  I started out really slow working out every other day.  I think my whole routine was about 45 min.  (15 minutes of cardio on a low intensity, 15 minutes of stretching, and one set of 10 reps. of weight training).  I gradually was able to add 10 to 15 minutes of swimming just prior to the membership ending.  I was able to return to my gym which would have been overwhelming if I didn't have a routine.  Once back at my regular gym I followed my original workout for over a month.  I then met with a trainer twice and told her my limitations and asked for mini workouts that I could do 5 to 6 days a week.  I do 30 -40 minutes on a stationary bike now (can't run to save my life) followed by a mini weight training session that works a body part or two for 20 minutes followed by stretching.  I stopped worrying about what the person next to me is doing because I can't compete, but I can go fast enough now on the bike to work up a sweat and to feel good.