Dreams can mean so many things, depending on what is going on in the life of the dreamer at that moment...it is said only the dreamer can truly know...
I do think this dream is significant for you, and worth pondering. So here is another possibility to consider:
A tower can be something that conveys a sense of security and value; a philosophy of life, a career, a way of being in the world. However when the dreamer is ready to move on, grow, and unfold something new in life, then the tower begins to feel like a place of isolation...as in the metaphor of the Ivory Tower.
So what your dream may represent is a very natural time of transition; wanting (and needing) to move on, while still reluctant to leave what has been so nourishing for you in the past.
When you see a tower in your dream it signifies high hopes and to see yourself holding onto something signifies your fear or realization that whatever it is you're holding is slipping away from you. Parents will often dream about holding their children tightly as their children grow older. In your case my guess would be that you have some kind of high hope or aspiration in your life that you feel you are losing for whatever reason and you're trying desperately to hold onto it.