New Mom Advice!!!!

So my little girl just turned 6 months old, she is my first child. I have been with her almost EVERY day since her birth except for two days. Lately I have been having thoughts of something terrible happening to her or being separated from her(I'm about to go back to work) or her dad and I splitting up and him taking her from me and my heart aches so much I want to cry and hold her and never let go. It's gotten so bad that I cannot sleep sometimes and I've went and got her out of her crib and brought her to sleep with me.... I don't know if it's because I am about to go back to work and she has to go to daycare or if it's something worse. Will this feeling go away and is it normal? Or do I need to talk to someone about my anxiety? Any advice on how to cope???