Separation Anxiety suggestions?

I am a SAHM and DS is 9 1/2 months old.  I am primary care taker, DH is often working or not home for one reason or another, my inlaws have been gone most of the winter and my parents come weekly to our house - we didn't get out a lot with the cold weather this winter, and even when we did he was with me.

So Separation Anxiety kicked in BIG time within the last 2 weeks and we just got home from a week at a hotel visiting family.  WOW was that difficult.  I couldn't be more than a foot away and rarely could anyone else hold him.  Not even my parents who he sees weekly.  It was difficult even getting him to bed last night in his own room again by himself.

 He just cries and screams to the point where he's spitting up and occasionally gives himself a bloody nose!  He's done this sometimes just going down for a nap and being left alone in his room.

I was planning on volunteering this summer 1 day a week for 6 hours and leaving him with my MIL.  I am suppose to start in 2 weeks.  And I will be 1 1/2 hrs from home so I can't run home if there is a problem.

HELP!

I am not certain my MIL can handle this at this point.  It really upsets her when he acts afraid of her or when he starts crying.  She can't get him to stop.  I don't have anyone else that can take him consistently.  Should I consider daycare?  I have family in the area that has their kids in daycare so I know I can trust the place if they can take him.

I can not volunteer if I have to... but that only means I will still be around all the time and I can't see that helping him.