I second One and Done. You SO need a schedule. I'm a SAHM, and it is MUCH harder to get to the "I really need to do x one day..." stuff than the stuff with real deadlines: freelance work, appointments, errands, etc. those HAVE to get done... Therefore, your "I really should do x someday..." stuff ALWAYS GETS shoved out of sight out of mind-and not done.
In order for me to paint (for myself as well as for income-so count it like a freelance "from home" job) I HAD to schedule everything else. From necessities to leisure stuff for myself and the kids. For me, I'm useless after dinner. I had to just face it. Anything and everything had to be done before that. So I quit being a vampire, started going to bed early, got up early and got all my housework (one hour or so on SCHEDULED projects to be completed by DEADLINES I created-for instance if I wanted garage cleaned out, I did an hour per week for two months and SCHEDULED those hours into my day as well as scheduling the "real deadline"), then baby stuff (breakfast, dressing, playing, errands, park, lunch) and then for 2-3 hours after lunch (during nap and as kids got older I trained them to comply) I PAINTED. I usually had a deadline of a show or commission, but still I HAD to create the real time slot for myself daily, or at least x amount of days per week (SCHEDULED). Then at around 3-4pm, I'd do something fun with kids, park, whatever, make dinner...done for the day-leisure slot, TV, books, bed.
I got a LOT done that way. And I usually schedule things pretty much like that with whatever I need to do myself being done in afternoon for 2-3 hours. Now my oldest homeschools so we do all her lessons, music practice, etc before lunch. It really hasn't changed my life much from when she was a toddler, but I had to move work outs and errands to later slots (and housework gets fudged :) after my productive window in afternoon, and now I handle two younger sibs. But believe me, on weeks where I have slacked off and NOT scheduled stuff-sometimes in an effort to "relax"...I feel myself being pulled under and nothing gets done-and that is not relaxing, it is depressing.
You need a schedule. Embrace your shyness, but do try to reach out socially a bit. I don't socialize much, because with my schedule-I don't have time to hang out much! I'm fine with that actually. People who need to be social schedule their social time into the picture. Ask for help when you need it. If there are some HUGE messes at home making it impossible to cope, ask the hubs to watch kids and leave you alone for time slots on SCHEDULED days where you tackle that. Or ask to hire an organizer to work with you for just a couple of days. I can relate to tight budget and tight time; no sitters, no housekeeping help, no daycare, no fun shopping budget to get some clothes for yourself- no BREAK-it's the norm for so many of us, but sometimes you NEED to splurge on help or find a way to get the help from family or barter.
I kept my gym membership through thick and thin as a lifeline, and they have daycare-lifesaver!! Keep with your running! To be honest, you have a lot more support than I did-no family in our state and my husband travels most of the time-so I KNOW you can do it. Just try to count your blessings daily and schedule, schedule, schedule! Good luck, it hurts to feel the way you are, I've been there, you can turn it around!