Is it normal to be scared and nervous, even if you're doing well?

[Joshua D.]

So first let me say, my wife and I got into real estate investing about a year ago. I am going to put below the RE deals that we have made, thus far. 

1. Duplex- Paid 16k-Worth 35k- Generating $1,280/month in rent

2. SFH- Paid 27k-Worth 75k- Generating $925/month in rent

3. SFH- Paid 36k-worth 90k- Generating $1250/month in rent

4. SFH- Paid 40k- Worth 85k- Will generate $850/month in rent

5. SFH- Paid 24k- Worth 35K-Will generate $950/month in rent

6. SFH- Paid 24k- Worth 65k-Will generate $750/month in rent

7. 4.6 acres of Land + utilities - Paid 11k- Worth 40k-Will sell for 22-32k

8. SFH- Paid 22k-Worth 52k- Will generate $750/month in rent

NOW, granted, these numbers don't include our utilities costs/mortgage costs, etc. 

(However, we are in less than 100k in debt total, around 71k to be exact right now.)

With us growing, we get nervous every now and again that we are doing the right thing. Sure, we've gained tons in equity, but then you get nervous wondering, "well what if i couldn't sell it?"

Do you ever get nervous about sinking so much money into real estate? Do you think that it's 100% worth it? Feeling victorious but a little fearful, is it jusitified? Is it normal to ever feel apprehensive at times, hoping and praying that you're doing the right thing?