Is it normal to be apprehensive when you finally get a positive?

My husband and I have been ttc for 8 months now. I got a for sure positive today. we both want another baby so bad. but tonight...i dont know..i just feel nervous. Have anyone even been a little scared when they finally concieved a much wanted baby? I just keep thinking " what if we cant afford another one?" " what if having a newborn and two year old is more than i can handle?" I thought about these things before i concieved, but when i saw that extra pink line i got not so sure...whats my problem?! i did the same thing when i got pregnant with my daughter? and then when we had her i realized that my worries were unfounded. so why am i nervous again when i know i did a good job with my daughter? Has anyone else experienced anything like this? Thnk you!