Write a Python function `convert_to_polar` that takes a complex number as input and returns its polar coordinates as a tuple `(r, theta)`. The polar coordinates consist of the magnitude `r` and the angle `theta` in radians.
#### Example Usage
```python [main.nopy]
convert_to_polar(1 + 1j) # Output: (1.4142135623730951, 0.7853981633974483)
convert_to_polar(-1 - 1j) # Output: (1.4142135623730951, -2.356194490192345)
convert_to_polar(0 + 0j) # Output: (0.0, 0.0)
```
#### Requirements
- Use the `cmath` module to perform the conversion.
- Ensure the function handles edge cases, such as when the input is `0 + 0j`.
Good luck!