Just good ol' organic kefir, small doses like 1/2 cup once or twice a day over about 3-7 days. But really, while you're doing parasite clensing, there's no point in taking probiotics since they'll just be half-killed by the parasite herbs. Kill first, replenish second. ;)
Definitely cut back on the the senna tea (senna is WAY too strong to take more than 14 days) and switch to plain P&B shakes. Check the descriptions of the herbs in the colon cleanser - fennel, rhubarb, dandelion are okay. Others may be too harsh. It's good to mix commercial cleansers with P&B shakes so you're not always subjected to the herbs.
Have you tried to do kinesiology yourself yet? There's a great method that's quite easy as taught by Machaelle Small Wright of Perelandra nature research institute. www.perelandra-ltd.com.