First off, congrats on your twin pregnancy! It's a whirlwind once the babies arrive, but you can absolutely do it yourself as long as you set realistic standards and pick what are the absolute must-dos and what aren't. Secondly, take all advice as just that, advice, not fact. You will find your own groove. You can pick and choose what you want to do or try, but the key with twins is FLEXIBILITY! I had ideals before my twinkies were born. Some of them had to change. It crushed me at first that I couldn't do everything I wanted, but I got over it. Please don't beat yourself up if things don't go the way you plan!
My twins are now 4.5 months old and so I remember very vividly what the beginning months are like. The first 2 months are definitely the hardest, but don't worry, things ease up! This is how a day typically looks like right now:
The babies are up between 5-6am for the day. I am asleep for this and DH is on baby duty. He feeds/changes and plays with them until 8:30 or 9 when I get up. He showers and gets ready for work while I throw something in the microwave for breakfast. The babies are playing under their activity gym. DH leaves for work and I scarf down my food and then sit on the floor and play and sing with the babies (I cannot stress signing enough. Babies LOVE it as you probably remember from when your DS was little)
Then as 10am approaches, I change diapers and then we have story time. Then I nurse them (at the same time with a twin pillow) and they are super sleepy and ready for a nap by 10. Once they are down, I swap loads of laundry, unload the dishwasher and reload, run the vacuum through the part of the house the babies are not in (shutting doors to vacuum inside room to keep noise level down) and then I run through and tidy (using a laundry basket to collect things to put away. By now, it's usually around 11:30. I sit down and have a little me time. As noon approaches, I slip the babies bottles of pumped milk (I started this after they hit 6 weeks and could go back and forth from breast to bottle) They don't even wake up fully, just enough to eat. When they stop suckling, I remove the bottles and they continue to sleep. This time I use to pay bills or work on knitting or any household project I want to work on. I usually am munching on lunch during this time too. If I'm tired, I nap with them.
As 1:30 approaches, the babies usually begin to stir. When they are awake, I change diapers and then nurse. Then we play on the floor together. As it nears 4pm, I set the babies in the seats (bouncy seats or nap nannys or swings will work) and I set them in the kitchen and I sing to them while I prepare dinner. SOmetimes I tell stories I make up or just talk to them about what I'm doing ot tell them about holidays or what-not. We eat at 5pm whether DH is home or not. I sing to them while I cleanup dinner and I leave the dishes for a couple hours while I start bedtime routine.
I start by playing with them on the floor after dinner for about 30 minutes. Then at 6pm, we take baths. One is in a seat while I bath the other one. Then the freshly bathed baby goes on the floor on a rubber mat, naked with a towel draped over for "naked kicky time" I do this to let their bottoms air out. They've never had diaper rash. After baby 2 is washed, I diaper and pajama them and we have stories until "lights out" at 7:30. Then we rock and gently sing to sleep as I nurse them. DH goes to sleep at 9pm and sleeps till 3am while I do baby duty. My babies still wake every 2 hours to eat. I go to sleep at 3am and DH wakes and does baby duty. I slip in a shower during part of story time while DH reads. During my 9am - 3am shift, I'm washing laundry (we cloth diaper, so every day laundry is a must) and I do the dinner dishes and wipe down during this time.
I don't have any older kids, but you can probably squeeze in 1on1 time with DS as you prepare dinner, fold laundry, etc. Multitasking really is a must.
For errands, I use a side by side double jogging stroller. It turns on a dime and glides soooo nicely. The babies sleep very easily in it. We did convertable car seats from the beginning. Mobys are awesome for everything.
It took some time to get into a routine that worked for us and getting the babies on a predictable schedule. In the beginning, they sleep at odd times and not always at the same time. I advise you to wake baby 2 when baby 1 wakes to eat and feed them both. Try to get them both to sleep at the same time. After a few weeks, you will see that they will start to go down and wake up almost within a minute or two of each other. They do get off sometimes, but then you just work to get them back on. In the very beginning, we did the bare minimum. Clean dishes and laundry were a must, so that's all I did. The floors were gross after a month, but we did what we had to do. It does gets easier as time moves on thankfully.
My MIL did stay with us for the first week and a half, but we were 100% alone after that with no friends or family over to help at ALL. One of my babies has a severe problem with his eye and we spend a fair of time in the hospital and to see specialists, but we still manage. It's tough, but it can be done if you make lists and prioritize.