I Started 37.5 Effexor This Morning And It's Now 12

I started 37.5 Effexor this morning and it's now 12 hours later and I feel really off. I was bent over my table and felt like I was falling. My mind is groggy I can't focus on much but the tv. I am always busy and I don't want to do anything at all. I also took a .5 lorrazep am about 3 hours ago and have been taking those for 3 years now. Should I stop taking the effextor? I don't want to feel this way