RPM's dipping and transmission is hard to shift

Well, about a week ago, I noticed my rpm’s would dip, momentarily while cruising below fifty mph. They would wind down, in a sense, and then return to normal for a little while even when lightly pressing on the gas. I went out of town yesterday, returned and dropped my buddy off at her house, put in park and tried to put it in reverse when leaving but it was hard to shift, a problem that was more noticeable since the last time I needed to shift. It was tough to get it into drive and I was worried sick all the way home. I have not driven it or tried it again since last night, but is it driveable to a mechanic or transmission shop? My Toyota dealership told me days earlier there was nothing they could do about the rpm's dipping unless the check engine light came on which as of last night still has not made an appearance.