How do I show I’m interested

I have a big crush on one of the IT guys at my jobs and I know he likes me as well. However, every time he tries speaking to me, I get really shy and end up not saying anything or nervously giggling.

He’s been distancing himself lately, probably cause he thinks I’m not interested. How do I show him I’m still interested?

Also, I normally wouldn’t date someone from work but we do completely different jobs and only see each other in passing or in the break room.