Your feelings are very common. Despite the fact that we know intellectually that once you BH have a family your avodas Hashem is very different then the more direct “spiritual experiences” you’ve been having until now, it is very hard emotionally and psychologically to make that switch. Depending on your baby’s schedule, you can certainly daven most of the davening at home. Also try to have around material on inyanai deyoma that you can read. If you have someone who you can swap time with so that each of you watch the other one’s kids for part of the time so that both of you can get to shul that’s great, but keep in mind that your main obligation at this point is not to be in shul.
An idea that I heard from Rabbi Ellis, shlita that I found very insightful is the concept that much of what we consider “spiritual experiences” (his term was “d’veikus bahashem”) is actually regesh — emotion. While regesh is definitely an important tool in avodas hashem, it is not innately spiritual — the ONLY way in this world to access true spirituality is to do what Hashem has told us to do. It is very helpful to remind yourself that what you are lacking on Rosh Hashana is the emotional experience of davening in shul — but not in any way are you lacking in your connection to Hashem, which comes as a result of doing his ratzon. It is now your job to try to access the same fulfillment without the aid of the “regesh” that helped you until now.
Good Luck!