It's been almost a month now - infidelity?

My husband came to me over Memorial weekend & told me he had been having an affair for the past year. Can't get into counseling until July 22 (first available appointment) & as time goes on, he'd thinking we don't need the counseling. We both want to work it out & I believe him when he says he truly regrets it & now knows I'm his life partner. He's more in love with me now than ever. So why do I feel so down? I just graduated with honors from Medical School in May. I'm 51 years young. I've been trying to obtain employment - jobs are scarce. My 11 year old granddaughter has been with me during the day while school is out & her mom is at work. Mom & her boyfriend are in the process of buying a house. I was really excited for her before my husband told me about his affair - and offered to help out as much as I can. She's asked me to help her clean her apartment, go through the final walk through, go shopping etc., and I haven't done any of that. By the time she comes & picks up her daughter, I just want to spend time with my husband. She knows somethings up & has inquired, however, I have told her that I'm just going through some personal issues. She knows it's between me & my husband, however, she thinks it's about money. I almost welcome that because I'd be devastated if she thought it was about any affair - so I just go with it. I want to feel happy again. I want to trust my husband again. How can I do this?