That's because you have a poor understanding of what it means to "offer it up".

You have the myth and you hold on to it (and there's a reason for this holding on that I won't go into today).

We offer something to God spiritually as an act of communion, an exchange with God.  

"Here is my pain/my struggle/my limitation/my problem, please give me grace like You promised you would.  I am only a child and can't do this anymore.  Help me. Hurry." (acts of humility, abandonment, faith, hope). 

We can offer things for various reasons..all good ones...all enabling a different and deeper unity with God, dialog with Him, encountering Him amid our troubles (or our joys). 

We can offer some distasteful work well done as an act of petition for someone else.

Rather than offering you a tissue, I offered you about 5 ways that you could quite quickly and beautifully sanctify this period of your life with God. 

That's an act of charity.  If you want a tissue of sympathy see a Jesuit priest.