OP:
You're getting a low credit because premium is low (duh).
You're getting low premium because volatility is low.
The higher the volatility, the higher the premium. Right now it's trading at roughly 10% volatility which is towards the 'very' low end of the spectrum. You may have been used to seeing 20%+ volatility in the previous month and set expectations accordingly.
The rationale behind this is the higher the volatility the higher the premium.
I believe the reason for the low volatility right now is that the general consensus is that it's another bull market and things can only get better from here. And if that's the general consensus, who wants to buy 'insurance'. Low demand, low price. Ergo, the pittance on the spread.
On the plus side, you're more likely to not have your puts assigned

So your return is lower but your risk adjusted return may be higher (10% return on a 20% probability of exercise versus 20% return on an 80% probability of exercise)... if one could measure such things.
At this point, you either want to increase the spread, go completely naked, choose alternative underlying or switch to buy-side on the option.
(Technically you could just buy 1-2 month out options at low volatility and 'hope' the volatility increases and re-sell the option). Yes of course this is a completely different trade tho
Good luck, choose wisely, and it's great your asking the right questions.