It's perfectly natural to be somewhat panicked, or worried about losing your sanity. Here is what I learned from the first few months of being a father.
Accept that you're in a new situation right now.
Becoming parents is the single biggest change in your life, ever. Many of your habits (chores, interests, hobbies) will have to be adapted, and while you figure out which habits change in what way, you're naturally going to feel stressed. Realize that feeling stressed does not mean that you're doing a poor job!
Focus on today. Don't worry about the future.
Yes, you don't have as much time for yourself as you used to. Still, you must take care of yourself to the extent needed so that you can take care of others (spouse, child). That sometimes means that the baby cries for two minutes while you go to the lavatory. That may also mean that some chores get done less regularly, or at bigger intervals than you're used to. It's okay. You only need to function right now, until you work out a new routine in the home.
Practically everybody understands that the first child is a big change. It may mean that you're less productive in the office, or that you put in fewer hours than you're used to; most workplaces understand and accept that, so use it to your advantage and don't stress about it. You'll catch up in the long run.
Don't be afraid to ask for help.
Some are fortunate to be near their extended family, who can help with some chores in the coming weeks. In two months time, you'll a grasp on your new routine and you won't need help anymore/as much. If you don't have family nearby, you can still ask friends to run an errand once in a while. If you're all alone, you're still two parents.
A feeding schedule is helpful.
Try to establish a regular feed/awake/sleep schedule. It might be every two hours, or every four hours. Let the baby breastfeed at those intervals, even if he doesn't want to at first. Having a regular schedule is immensely helpful, and you'd be surprised how early that can be trained. As soon as that schedule is roughly in place, both parents can wind down a bit because the next sleep phase can be planned out.
Let mommy sleep.
While you're at home, allow your wife to sleep whenever needed; best while the baby is asleep too. Newborns often don't feed on a regular schedule yet, so it can be very tiring for the wife to be always-on-standby for breastfeeding. Let her sleep and recharge, to be ready to handle on her own when you're back to work.