YES!! Always tell your medical or dental provider if you're taking medication prior to *any* procedure. It likely won't be a problem with having fillings done, but you want to be sure the Dentist knows so that any local anesthetic they use won't interact with the medication you've already taken. Most Dentists now want updated medication lists at each follow up.
It's in *your* best interest to keep your Dentist updated; please do tell them. And again, I can't imagine a sedative will interact with the local but do let them know, just to protect yourself. Do you have someone taking you and bringing you home or are you taking public transport?
Also, pat yourself on the back for making it to an exam and making the follow up appointment for the fillings. That's half the battle (literally!)....because Dentistry techniques, training and tools/local anesthetics available have dramatically improved in even just the last decade, you may very well find your appointment tomorrow to be a huge difference from any procedures you had a decade ago. I promise, I'm not making this up to deceive you! Deep breaths in and slowly out before your appointment....what worries you most? How do you feel about your Dentist?