TeeSpring- Lifetime vs. Daily FB Budget, etc? HELP!

First off, we are selling TeeSpring through Facebook. We have been at it for about 8 months.

We started off using Clicks To Website ads and then switched over to PPE. When we did that a few months ago, we saw tremendous growth and better sales. We were also launching 40-70 campaigns each day. Recently things are slowing down for us, so we are trying different methods.

We also were using a Daily Budget that started around $5 and increased over time if the campaign was selling. We ran them for 10 to 14 days. We tried a $10 spend to start but that seemed to spend too much on losers.

Right now, we are trying something different to try to bolster sales. We went to Lifetime Budgets of $70 for 7 days. We are using PPE and launching everything on Wednesday. We want to make a decision on the campaigns by Friday (turn them off or boost the spend).

So... yesterday we spent close to $5000 on 400 plus campaigns with dismal results. I want to stop the bleeding, but I'm not sure what we should do.

So here are my questions:

Is Lifetime Budget better than daily? We saw some campaigns spend nearly $20 the first day with Lifetime!

Is PPE better than CTW? We saw great results with PPE in the beginning- on a smaller daily budget. But maybe it's because we ran longer campaigns at a smaller spend limit and gave them time to "get rolling" with comments, shares, tags, etc.

We are kind of unique in that we sell into hundreds of niches. We have some that are our best, but I think we may be running through them too much and "wearing out" the niche. As I said, we had great success early on- we were averaging 400- 500 sales per day and have been steadily dropping. We are lucky to hit the 200 mark these days. That's the reason for the changes we made. Now I'm thinking we maybe we overreacted and made the wrong move(s).

Any suggestions would be greatly appreciated at this point- thanks!