You have received great advice, get on a good summer league team, work on your velo, and don't worry about the pro prospects until it is evident you have those skills. 86-88 in today's world is nowhere near where you need to be.
Frankly 90 is not that unusual these days, for serious pro interest you will have to sit 90 (minimum) and be touching 94-95, anything less than this you are just kidding yourself. My son has a friend from his program (CWS team) who sat 90 touched 94 and was taken as a un-drafted signee. My son was 88-90 touching 93 and did not bother with the interest in him as he enjoyed his college career and with borderline numbers he knew it was time for him to move on.
My advice is to work hard, enjoy the next couple of years, as you are truly blessed to be playing college ball, and it will be self evident whether or not you are pro material or not.