my son just turned 3 months and is this way. he is finally starting to outgrow the fussiness. He has fussed all the time. My duaghter never was that way, she was great. So i have learned they have their own personalities. He has the acne still, and I was told that it can tkae up to 9 months to acutally clear up. So don't worry about that at all.
I would suggest switching formulas if you think that might be it. I would switch to Nestle Good Start. it really is a much better formula. It is already fully broken down just as far as any other "special" formula and it's a TON cheaper.
I would suggest also wear your baby. that is really what helped my son out. I would wear him whenever needed he would fall asleep within minutes, and i would continue to wear him so he would sleep.
I know what it's like as I have a 2 year old as well, but remember this period will only last a few months. Ask for help from others and there are still things you can do with both the baby and the 2 year old during the day. we danced a LOT in my house, and still i need to wear my son. Then i am intereacting with my daughter and still taking care of my son the way he needs it.