Ever since I made 5 subdomains, my pagerank lowered. I used to be on top of google for over 60 pages of my website, until I added 5 subdomains to my site. However, I don’t need these subdomains, therefore I removed them.

So my question is, will my page rank go back up to the same level it was before?

Google penalizes you if you use sub-domains to link to your main page. They are also pretty secretive about their practices. I can assure you that raising your page rank is still possible, but it is impossible to say if the penalty goes away or not. It would probably only take a few more natural links to get you back to where you were.